Pistachio Rhubarb Tarts
Get ready to welcome spring with open arms with these pistachio rhubarb tarts! Pistachio tart shells filled with a rhubarb compote brightened up with orange, rose, and cardamom then topped with torched meringue. Nothing could be better this spring!
What Pairs Well with Rhubarb?
Rhubarb is my favorite springtime produce. Whenever I see vibrant pink/red rhubarb in the grocery store I know that spring has sprung and winter is behind us. Rhubarb is very very sour, so when you bake with rhubarb, it always needs sugar to sweeten the deal. Pistachios always go great with rhubarb because as a fattier nut, it helps cut down that sourness and also provides a contrasting green color component to the tart. Adding the rose gives it a pop of floral, but remember that a little rose goes a long way. Plus, these pistachio rhubarb tarts a perfect treat for those who are gluten and/or dairy free. It’s a win win win.
A Brief History on Rhubarb
Despite being used for many dessert recipes, rhubarb is actually a vegetable and was not used for culinary purposes! Rhubarb roots were first used by the Chinese five thousand years ago as a laxative and wouldn’t hit the kitchens until the 1820’s. In fact, it was one brave woman in London with a knack for tarts and home grown rhubarb who decided she was up for the pastry challenge. The combination of sugar becoming affordable and rhubarb being available before any spring vegetables made it a recipe for success after hard winters.
Despite how delicious the rhubarb is, the leaves are actually lethal. Rhubarb leaves have high concentrations of oxalic acid which can be lethal to humans in certain doses. Unfortunately, the English learned that the hard way! Read a whole lot more on rhubarb here!
About the Ingredients
- Pistachios: You can use regular, unsalted, or go fancy and use Sicilian which are greener and a lot more expensive.
- Almond flour: Most grocery stores and wholesale clubs supply this. If not, you can purchase it online.
- Rhubarb: Always pick the most vibrant ones you can find. If your grocery store’s rhubarb is sub par in color, you can always adjust with food coloring. I usually go big and get at least 10 stalks; extra compote can be spread on toast or used for my thumbprint cookies!
- Rosewater Completely optional. You can get rosewater in most liquor stores. Some people find adding flowers to food a bit like having soap for dessert, but I find the floral sweetness pairs perfectly with the tart and sour rhubarb.
Major Allergens Present: Nuts, eggs
About the Equipment
- Food processor: Optional but will save time and energy finely chopping.
- 4″ fluted tart shells: You will want to spray these heavily as the crust has a tendency to stick!
- Hand or stand mixer: Also optional but helps a lot when whipping up meringue. For a hand mixer you will use the beaters, and for a stand mixer you will use the whip. If you do not have a mixer then you will want a sturdy whisk and a lot of elbow grease.
- Piping bag and tip: I use industry sized piping bags which I buy online. They are much easier to manage than those wimpy bags from your craft store.
- A blowtorch: You can either buy one from a specialty kitchenwares store or from a hardware store. I promise you they are cheaper and actually better from the hardware store.
How to Make Pistachio Rhubarb Tarts:
Make the pistachio tart shell:
This is a gluten free and dairy free tart shell made with nuts, nut flour, sugar, and an egg to bind it all together. You need to chop the nuts very finely or else the rhubarb compote may leak through the cracks caused by large pistachio pieces. You can make your life easier by using a food processor if you have one. When it comes to shaping in your tart tins, I suggest dividing the “dough” equally into the tins first. Wet your fingers first to prevent sticking then start pressing it into the tins.
I’ll start with the bottom then pinch it into the sides. No need to refrigerate; it is ready to bake. Rotate halfway through baking for even coloring and baking. It’s ready to come out of the oven when the edges just start to turn brown. We want to be careful of over-baking as we want to keep that gorgeous green color!
Make the rhubarb compote:
With the sourness of the rhubarb we need to add a decent amount of sugar. This compote still allows for the tartness of the rhubarb to come through, however, if you prefer something sweeter, go ahead and increase the sugar by 10-15%. This method uses a cooked sugar method which helps keep a good water content to the compote. Start by mixing the sugar with just enough water to make wet sand, and allow it to cook until the bubbles become slow and lethargic. Technically the temperature is 250*F (the same for Italian meringues!), but since compote isn’t super scientific, I usually just eyeball it.
Once the sugar is at temp, throw in the diced up rhubarb and immediately mix. This will be tough because the sugar will immediately start to cool down and thicken. Keep stirring until everything settles down and the sugar thins out. At this point we add the extra flavor enhancers (orange, cardamom, optional rosewater), and reduce the heat to medium. Allow it to cook until almost all the juices have cooked out. Make sure to stir every other minute otherwise the bottom will burn. If your rhubarb was not naturally a beautiful color, then add in a few drops of red and/or pink food coloring to brighten it up.
Whip up the swiss meringue:
Decorating with meringue is of course optional but highly recommended; it’s sweetness helps cut the tartness of the rhubarb. There are three types of meringues: American, Swiss, and Italian. Each one is cooked differently. American style is not cooked at all and is the least stable. Swiss style has the egg whites and sugar cooked until the sugar dissolves and has a medium stability. And Italian style cooks the sugar to 250*F and is the most stable. Depending on what you’re making depends on what stye of meringue you should use.
Since we are just decorating, Swiss works well here; stable but not super stable. You simply warm the whites and sugar over a double boiler until the sugar dissolves whisking minimally. I will just stick my fingers in and feel if there any sugar granules. Then you whip on high speed until stiff peaks form. You can’t overwhip Swiss meringue, but you do need to keep it in motion until you use it otherwise it will become blocky. How you pipe and decorate is your choice.
Finish the pistachio rhubarb tarts:
Once you’ve finished all of the components, it is time to compose the tart! Evenly distribute the compote between the tarts. If you need these to last a few days, use can brush the inside of the shells with melted white chocolate to act as a barrier and prevent the shell from becoming soggy. After the compote is added, decorate with the meringue.
You can pipe with a piping back and tip or you can spoon it on rustic style. Don’t forget to bust out the blowtorch if you are equipped (the best part in my opinion!). To torch, use even fluid motions. Less is more and you can always go back over it. Adorn with roughly chopped pistachios.
Extra Tips and Tricks For Successful Pistachio Rhubarb Tarts:
How to Make Swiss Meringue:
- Use fresh egg whites as opposed to carton egg whites. Fresh will always whip up better.
- Make sure no fat gets in the bowl or on your whip attachment! Fat will always destroy a beautifully whipped meringue. You can wipe the bowl and attachment with a vinegar dampened paper towel if you’re nervous about it.
- You can’t over-whip Swiss or Italian meringue so turn that mixer on high and let it rip! However, once you have it going it must be kept in constant motion or else it will be less smooth and more chunky. If I’m not quite ready for it yet, I’ll turn my mixer down to 1-2 speed (low). If you want to use it right away, make sure to have the tarts ready for the meringue before making it, or you can scoop the compote into the shells while it’s cooking and whipping.
- When warming the whites and sugar together, just warm it until the sugar is dissolved. Help it along by whisking now and again.
How to Fill and Use a Piping Bag:
- Insert the piping tip and cut a hole accordingly. Push some of the bag into the tip to prevent any leakage.
- Fold the the top quarter to third of the bag over and hold the bag there. Spatula your batter into the bag wiping the spatula with your hand through the bag.
- Fold the top back over and hold the top of the bag with your non-dominant hand. With large piping bags I will actually twist the end and put under my arm pit for safe keeping.
- Squeeze the center of the bag and twist. This your pressure point and your control point of the bag. The further from the tip, the more strenuous and less control you have over the bag.
- Use the meat of your hand to then squeeze out the contents. Release to stop.
How to Spice Up These Pistachio Rhubarb Tarts:
- Replace half the orange juice with whiskey and remove the rose all together.
- Fold in some fresh strawberries after the compote has cooled.
- Instead of orange, rose, and cardamom, use lemon and basil.
- Use a different nut if you do not like pistachio! Almond and/or walnut would both go great.
Life Expectancy, Storing, and Freezing Capabilities:
- Store the compote separately in a container in the fridge for up to 3 weeks or in the freezer for up to 3 months.
- Keep in an airtight container and store the tart shells at room temperature for up to 7 days.
- Store pistachio rhubarb tarts covered or uncovered refrigerated for up to 5 days. After 1 day the tart shells get a little soggy, and there may be some rhubarb leakage, but they will still taste great.
Troubleshooting Pistachio Rhubarb Tarts:
- My tart shell won’t come out of the tin! You didn’t spray it well enough! Release some of the edges with a knife, heat the tart tin over an open flame then gently bang out on the table.
- My rhubarb compote is is really watery! You didn’t cook it long enough and evaporate that water out! You can either cook it down some more, or you can let it sit in a fine, mesh strainer for 5-10 minutes.
- My rhubarb compote is an ugly color! That’s okay; we cannot control the color nature. If I was not blessed with a lovely pink color for rhubarb then I add a few drops of red food coloring.
- My meringue will not whip up! There may be some fat in the bowl! We’ve got to start over here. Clean the bowl and attachment/whisk thoroughly and give it a wipe with vinegar. Another issue could be the volume vs size of your stand mixer bowl. I have a 6 qt, pull up Kitchenaid mixer which needs larger quantities of meringue to whip up fully. For this, either increase the amount of meringue (I would double just to be safe) or hold the bowl higher to allow the whip attachment to hit everywhere.
Something else going wrong? Reach out and we will troubleshoot together!
Pistachio Rhubarb Tarts with Rose
Equipment
- Food processor optional
- 6 ea 4" fluted tart tins
- Hand or stand mixer optional
- Piping bag and tip
- Blowtorch
Ingredients
Pistachio Tart Shell
- 142 g Pistachios, unsalted plus extra for garnish
- 2 Tbs Granulated sugar
- 52 g Almond flour
- 1 pinch Kosher salt
- 1 ea Whole egg
Rhubarb Compote
- 660 g Fresh rhubarb
- 200 g Granulated sugar
- ½ ea Orange zest and juice
- ¼ tsp Cardamom, ground
- 1 Tbs Rosewater Optional
Swiss Meringue
- 2 ea Egg whites or 60g
- 120 g Granulated sugar
Instructions
To prepare the pistachio tart shells
- Preheat your oven to 350°F and spray your fluted tart tins with pan spray.
- Chop or process in your food processor the pistachios until very fine. Mix in the Sugar, almond flour, and salt.
- With a spatula, mix in the egg until a paste forms.
- Evenly divide the dough into your prepared tart tins, and then firmly press and mold into the tin.
- Bake for 15-18 minutes, rotating halfway through, or until it starts to turn a light golden brown.
To prepare the rhubarb compote
- Roughly chop the rhubarb into ¼-½" slices and set aside.
- Combine the sugar in a medium pan with enough water to make wet sand. Cook until the bubbles become slow and lethargic.
- Quickly add in the rhubarb and stir with a spatula until the sugar coats the rhubarb. Keep stirring until the sugar has mostly dissolved with the rhubarb. Reduce the heat to medium.
- Add in the orange juice, zest, cardamom, and optional rose water.
- Allow to cook stirring every minute or two so it will not burn, and cook until there are no more or minimal juices left in the pan. Remove from heat and allow to cool.
To prepare the Swiss meringue
- Whisk together the sugar and egg whites in the bowl of your stand mixer. Cook, whisking occasionally, until the sugar dissolves.
- Whip on high speed with your hand mixer and beaters or stand mixer and whip attachment until stiff peaks. Reduce to low speed if not ready to use.
To finish the pistachio rhubarb tarts
- Remove the pistachio tart shells from the tin. Divide the rhubarb rose compote evenly amongst the tart shells.
- Insert your tip of choice into your piping bag and fill with the meringue. Pipe decoration as desired and torch evenly with a blowtorch.
- Adorn with roughly chopped pistachios.
Nutrition
I could not have been happier with how this turned out!! So yummy for spring and gluten free for my daughter!
So happy you had a delicious option for your daughter!
Loved this gluten free dessert! 10/10 recommend adding the optional rosewater 🙂