In a medium mixing bowl stir together flour, baking powder, sugar, cream of tartar, and salt. Mix well to distribute the baking powder and the salt.

Using a pastry blender or fork, cut shortening into flour mixture until the mixture resembles coarse crumbs. If you use butter, be sure it is chilled. (Mixing by hand softens the shortening, making the dough sticky and hard to handle.)

Gently push the flour-shortening mixture against the sides of the bowl, making a well in the center. Pour the milk into the well all at once. Using a fork, stir just until the mixture follows the fork around the bowl and forms a soft dough.

Turn the dough out onto a lightly floured surface. Knead gently 10 to 12 strokes.

On the lightly floured surface, pat the dough to 1/2-inch thickness (or roll it out with a lightly floured rolling pin, if desired). Sprinkle a little flour over dough.

Cut biscuit dough with a 2-1/2-inch round biscuit cutter, pressing the cutter straight down. Be careful not to twist the cutter or flatten the cut biscuit edges or you won't get straight-sided, evenly shaped biscuits. Dip the cutter into flour between cuts to prevent sticking. If you do not have a biscuit cutter, use a straight-sided glass. Or, pat the dough into a 1/2-inch-thick rectangle and cut into squares or triangles using a sharp knife.

Using a metal spatula, carefully transfer the cut biscuits to an ungreased baking sheet. For crusty-sided biscuits, place about 1 inch apart. For soft-sided biscuits, place biscuits close together in an ungreased baking pan.

Reroll scraps of dough and cut into biscuit shapes. Try to cut out as many biscuits as possible from a single rolling of dough. Too many rerollings of the dough causes biscuits to be tough and dry.

Bake biscuits in 450 degree F oven 10 to 12 minutes or until biscuits are golden on the top and the bottom. Serve warm. Makes 10 biscuits.