Preheat your oven to 450°F (232°C).

In a large mixing bowl, sift together flour, sugar, salt, baking powder, and cream of tartar.

Cut the cold butter into small cubes and add it to the flour mixture, then work it into the flour until it resembles coarse crumbs.

In a small bowl, whisk together the egg and milk, then pour this mixture into the flour mixture and stir gently.

Turn the dough out onto a floured surface and knead it gently 10-15 times.

Pat the dough into a thickness of about ¾ to 1 inch and cut out biscuits.

Place the biscuits on a greased baking sheet and bake for 10-15 minutes until golden brown.

Allow the biscuits to cool slightly, then serve warm.