Simple Tomato Sauce
1 (28-ounce) can whole peeled tomatoes
2 tablespoons butter
½ sweet onion, peeled
Heat all ingredients together over medium heat. Simmer for 45 minutes, then purée with stick blender until onion is broken up. Salt and pepper as needed.
Cut eggplant into ½-inch-thick medallions. Spread eggplant slices between double layers of paper towels and plates to press out moisture. This should take 45 minutes. During this time, prepare the egg wash, breading and tomato sauce.
Whisk 4 eggs with 2 tablespoons water in pie plate. Mix rice flour with salt and pepper in another pie plate.
Preheat oven to 425°. Grease parchment-lined baking sheets with 2 tablespoons of olive oil each. Dip eggplant in egg wash, then in flour mixture, coating both sides evenly, and lay in a single layer across the baking sheet. Do not crowd. Drizzle another 2 tablespoons olive oil over top.
Bake for 16–20 minutes, flipping slices midway.
To assemble the stacks, layer eggplant, sauce and cheese then repeat two more times on the prepared baking sheets. Return to oven and bake at 475° F for 15 minutes or until cheese is melted and brown.