The Preparation
Preheat oven to 450°F.
Whisk together flour, baking powder, cream of tartar, sugar, baking soda, and salt.
Cut cold butter into flour until mixture resembles coarse crumbs.
Whisk egg into milk and add to flour mixture, stirring until just combined.
Turn onto floured surface and gently fold a few times.
Pat to 3/4 inch thickness and cut out biscuits.
Bake at 450°F for 10-12 minutes until golden.
