Combine yeast, water and 1 teaspoon sugar in a small bowl. Set aside.

Combine flour, cornstarch, baking powder, baking soda, cream of tartar, salt and sugar in a large bowl. Add yeast mixture, vegetable shortening and milk. Stir to combine. The dough will be shaggy at this point. Cover the bowl, and let stand in a warm place for 45 minutes.

Turn dough onto board or waxed paper dusted with ¼ cup flour. Knead the dough gently for a minute or two until it feels smooth and pliable. Roll dough with lightly floured rolling pin until it is about ¾-inch thick; cut with a biscuit cutter or the rim of a glass dipped in flour. Place on a lightly greased cookie sheet or parchment paper. Cover with a damp paper towel and let sit for 30 minutes to an hour.

Preheat oven to 400° F. Lightly brush tops of biscuits with melted butter. Bake for 15 minutes or until the tops are golden brown. Remove from oven. Yield: 12 biscuits.

NOTE: To save unused biscuits, keep in zip lock bag. To reheat the next day, pat top of each biscuit with a little water and bake at 350° F for about 10 minutes. These will freeze well after being cooked.