Preheat the oven to 425 degrees F. Line a baking sheet with parchment paper. Place the flour, baking powder, cornmeal and salt in a bowl and whisk to combine. Cut in butter until pea-sized crumbles form. Add the milk and stir just until dry ingredients are moistened. Transfer dough to floured work surface and knead into a ball. Press dough into a 3/4" thick disc. Cut dough into rounds with a 2" cookie cutter. Place on the baking sheet. Bake 15 minutes, or until puffed and golden.