Preheat oven to 400°F. Grease a baking sheet or line with parchment paper.
Mix eggs and buttermilk in a small bowl and set aside. Place baking mix in a large bowl. Using a fork or pastry blender, cut in cold butter until it’s the size of small peas. Add egg mixture to dry ingredients with optional add-ins and stir until evenly moistened.
Turn mixture out onto a gluten free floured surface and knead briefly to form a dough. Pat dough out to 1 inch thick. Fold the dough in half over itself and pat out again to 1 inch thick. Repeat folding and patting twice more. Cut biscuits and transfer to the baking sheet.
Brush the top of each biscuit with melted butter, if desired. Bake until golden-brown, about 20 minutes.
