Measure all ingredients precisely.

Combine the dry ingredients: flour blend, xanthan gum, salt, sugar, and leavening agent.

Cut in the cold butter until the mixture looks like coarse crumbs.

Add the buttermilk and egg, mixing just until combined — do not overmix.

Turn the dough onto a floured surface and gently pat it down (do not use a rolling pin). Cut out biscuits with a biscuit cutter or glass, pressing straight down without twisting.

Preheat the oven to 425°F (220°C). Place the biscuits on a parchment-lined baking sheet, slightly touching each other.

Bake for 12-15 minutes, until the tops are golden and the edges are crisp.