Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.
In a large bowl, whisk together the flour, baking powder, baking soda, and salt.
Cut the cold butter into the flour mixture until it resembles coarse crumbs.
Stir in the buttermilk until just combined, then gently fold in the cheddar and jalapeños.
Turn the dough onto a floured surface, pat it to about 1-inch thickness, and cut out biscuits using a round cutter.
Place the biscuits on the prepared baking sheet and bake for 15-18 minutes or until golden brown.