Heat oven to 450 degree F. Stir together 2 cups all-purpose flour, baking powder, sugar, cream of tartar, and 1/4 teaspoon salt. Cut in 1/2 cup butter, margarine, or shortening until mixture resembles coarse crumbs. Make a well in the center. Add 2/3 cup milk all at once; stir until moistened. Turn dough out onto a lightly floured surface and knead by gently folding and pressing it 10 to 12 strokes or until nearly smooth. Pat or lightly roll dough to 1/2-inch thickness. Cut with a floured 2-inch biscuit cutter. Place biscuits 1 inch apart on an ungreased baking sheet. Bake about 10 minutes or until golden brown. Cool on a cooling rack.

Meanwhile, for the sauce melt 2 tablespoons butter or margarine in a saucepan. Add flour, the 1/4 teaspoon salt, and 1/8 teaspoon pepper. Add the 1-1/4 cups milk; cook and stir until thickened and bubbly. Cook and stir 1 minute more. Add sherry and shredded cheese, stirring until cheese is melted. Keep warm while preparing eggs.

Beat together eggs, the 1/4 cup milk, 1/4 teaspoon salt, and 1/8 teaspoon pepper in a bowl. Stir in chopped ham or Canadian bacon and basil. Melt 2 tablespoons butter or margarine in a large skillet. Pour in egg mixture. Cook over medium heat without stirring until mixture begins to set on the bottom and around the edges. Lift and fold partially cooked eggs so uncooked portion flows underneath. Continue cooking until eggs are cooked throughout but are still moist.

To serve, split biscuits; spoon some eggs onto each biscuit half. Spoon a little sauce over eggs. Serve open-face. If desired, garnish with fresh basil leaves. Makes 8 to 10 servings.

Make-Ahead Tip: Prepare the biscuits; freeze in a covered container up to 1 week. Before serving, wrap in foil and heat in a 350 degree F oven about 10 minutes. Make the sauce and refrigerate in a covered container up to 1 day. Reheat in a saucepan, adding a little milk to make sauce of desired consistency.