-=OR=Half and Half Salt, pepper To make crust, sift together cornmeal, flour, 1/2 teaspoon salt and pepper. Cut in shortening until mixture resembles coarse crumbs. Add water, 1 tablespoon at a time, stirring lightly until mixture forms ball. Turn out onto lightly floured board and roll dough to 13-inch circle. Fit loosely into 9-inch pie plate or quiche pan. Fold edge under and flute. Arrange cheese slices on bottom of crust. Fry sausage until cooked and crumbly. Drain off fat. Sprinkle sausage on top of cheese, then top with green onions. Lightly beat eggs in bowl, stir in whipping cream and season to taste with salt and pepper. Pour over cheese and chorizo mixture. Place on bottom rack of oven and bake at 450F 15 minutes. Reduce heat to 350F and bake additional 25 to 30 minutes. Let stand 10 minutes before cutting. (C) 1992 The Los Angeles Times Karen Mintzias