Prepare a sheet pan with parchment paper or a silicon baking mat and set aside.
Combine the dry ingredients together (except the black pepper) and slice the butter into ¼" slices. Add the butter to the dry ingredients.
Using your hands, rub the butter into the flour to create long, flat flakes. Continue until all butter pieces are flat and evenly dispersed throughout the flour.
Add in the buttermilk, egg, black pepper, and cheddar cheese and hand mix until a dough comes together. Don't overmix and overwork the flour! It's okay to have some loose crumbles.
On a floured surface, roll to about one-inch thick. Do a trifold by folding one third onto itself and the remaining third on top. Roll down to one-inch thick.
Using your three-inch ring cutter, cut out your biscuits and place roughly two-inches apart on your prepared sheet pan.
Place in the fridge for 30 minutes. In the meantime, preheat your oven to 375℉.
Scramble one egg and brush the tops of the biscuits. Top with pepper and flaky sea salt.
Bake for 20 minutes, rotating half way through or until the tops are golden brown. Allow to cool on a wire rack before enjoying.