Peel the eggplant and trim off the ends. Slice it into rounds about 1/2-inch thick. Line a baking sheet with parchment paper. Preheat oven to 400F.
In a medium mixing bowl, combine the cornmeal, brown rice flour, garlic powder, salt, onion powder, and black pepper. Add the almond milk and lemon juice and stir until smooth. You should have a batter a little thicker than pancake batter. If it seems dry, add a splash of non-dairy milk; if it's too liquidy, add more flour.
Dip each eggplant slice into the batter and turn it to coat both sides and edges well. Holding the slice between two fingers, allow any excess batter to drip back into the bowl, and place the eggplant on the baking sheet. Repeat with as many slices as you can fit on the baking sheet, being careful that they do not touch. (If your baking sheet is small, you may need to make two batches; batter can thicken between batches, so add more liquid if necessary.)
Place in the oven. After 20 minutes, remove and gently turn each slice–you may have to hold the parchment paper and peel it from the eggplant. Replace and cook until outsides are brown but not burning, about 15 more minutes.
While the eggplant is baking, make the cashew parmesan and the sauce: Place the cashews in the food processor along with the nutritional yeast and process until finely ground. Remove half to a small bowl and set aside. Add the bread to the cashews remaining in the processor and pulse until crumbled.
Place all sauce ingredients in blender and blend at high speed until completely smooth. Blend again briefly just before using.
When the eggplant is done, assemble the casserole: Reduce the oven temperature to 350F. Oil an 8x8-inch or similar sized casserole dish. Place half of the eggplant slices on the bottom of the dish. Spoon half the tomato sauce and pour half the cheese sauce over the eggplant and sprinkle lightly with cashew parmesan (the bowl without the bread crumbs). Repeat the process with the remaining eggplant, spaghetti sauce, and cheese sauce and sprinkle the bread crumbs on top. Bake uncovered for about 25-30 minutes, until slightly browned. Sprinkle with fresh basil just before serving.
For a much simpler recipe, skip the breading of the eggplant by sprinkling it with the seasonings and baking it until it's tender, about 20 minutes. Use 2 slices of bread instead of one, and process it with all of the cashews and nutritional yeast; use between layers and on top. This will reduce the calories by 53 per serving and the fat by .81g.Exact nutritional content will vary depending on the type of spaghetti sauce and other ingredients you use.