Drain the cottage cheese in a sieve for several hours to remove the liquid. Preheat oven to 375 degrees F. Make piecrust according to your favorite recipe and fit into pie plate. Cook onion in butter or oil until translucent. Beat eggs in a mixing bowl. Mix in sauteed onion, drained cottage cheese, and basil, and season with salt and pepper. Pour egg mixture into the pie shell. Arrange tomato slices on top. Sprinkle with Parmesan cheese (as much as you like) and bake for approximately 45 to 50 minutes or until, when you wiggle the pie, it appears set. Remove from oven and let sit for 5 minutes before cutting.