Preheat oven to 350ºF. Lightly grease a baking sheet.
Sift together in a bowl, the flour, sugar, baking powder, salt and cream of tartar. With a fork, blend in butter until the mixture resembles coarse meal, stir in egg and milk.
Turn dough out onto a lightly floured surface. Knead dough lightly once or twice and shapr into a ¾” thick circle. Cut biscuits with a 2” cutter. Place on prepared baking sheet. Bake for 15 minutes or until golden brown.