Line a baking sheet with parchment paper. Heat the oven to 450°.
In a food processor or large bowl, combine the flour, baking powder, salt, and soda. Cut the butter into small pieces and add to the mixture. Work in with fingers or with the food processor until the mixture looks like coarse crumbs.
If using the food processor, transfer the mixture to a large bowl and make a well in the center. Add the buttermilk and stir with a wooden spoon until it clumps together.
Turn out onto a lightly floured surface and knead just a few times to get the dough together. Pat the dough out to a 3/4-inch thick circle and cut out with 2-inch cutters.
Gently put the scraps together and pat out again, cutting out biscuits until all the dough is used. Work the dough as little as possible.
Arrange the biscuits on the baking sheet and bake for 10 to 12 minutes, until golden brown on tops and bottoms.
Makes 8 to 10 biscuits.