1For crust, prepare using store bought or your own recipe, adding garlic salt to flour mixture if you are making your own crust. Roll and press crust into 9-inch quiche dish or pie plate. Brush edge of pie crust with beaten egg. Bake 10 minutes or until set and lightly browned. Cool while preparing filling. REDUCE OVEN TEMPERATURE TO 350ºF.
For filling, cook and stir onion in 1 tablespoon oil in small skillet on medium heat until softened. Spoon into cooled baked pie crust. Sprinkle with mozzarella cheese.
Combine remaining 1/4 cup oil, basil, salt, pepper and garlic in blender. Blend at high speed until smooth.
Beat 4 eggs in large bowl at medium speed of electric mixer until foamy. Reduce speed to low. Add half-and-half, ricotta cheese and 1/2 cup Parmesan cheese. Beat until well blended. Add basil mixture slowly. Beat until well blended. Pour over cheese in pie crust.
Bake at 350ºF for 20 minutes. Remove quiche from oven. Top with tomato slices. Return quiche to oven. Bake 30 minutes or until center is firm. Sprinkle tomatoes with remaining 1 tablespoon Parmesan cheese. Serve hot, warm or cold. Refrigerate leftovers.