01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together flour, baking powder, baking soda, salt, and pepper until evenly distributed.
03 - Add cold butter cubes to flour mixture. Using a pastry cutter or fingertips, work butter into flour until mixture resembles coarse crumbs with some pea-sized butter pieces remaining.
04 - Stir in grated Gruyere cheese and chopped sage until evenly distributed throughout flour mixture.
05 - Pour cold buttermilk over flour mixture and mix gently with a fork just until dough comes together. Do not overmix.
06 - Turn dough onto lightly floured surface. Pat into 1-inch thick rectangle. Using floured 2.5-inch biscuit cutter, cut straight down without twisting. Gather scraps and repeat.
07 - Place biscuits 1 inch apart on prepared baking sheet. Brush tops with milk or cream if desired. Bake 14 to 16 minutes until golden brown.
08 - Cool slightly on baking sheet, then serve warm.