I started with one of those horribly overgrown zucchinis and an eggplant. They were organic, so I did not peel them. Peeling is optional. The eggplant has a slightly thicker skin. It just depends what you like.
Slice into rounds of uniform thickness. Mine were probably about 1/4 inch thick. Maybe 1/3.
I had A LOT of vegs so I beat 4 eggs in a bowl for dipping.
In a 13x9 I mixed about 1 cup. flour, 1/2 c. (at least) parmesan cheese, garlic (probably a couple tsp. because I like garlic), and some pepper.
Heat some vegetable oil in a frying pan.
Dip the pieces of eggplant into the egg, then into the flour mixture. When you have enough coated to fill your pan, fry 'em up. You are just browning them, not cooking them through. Maybe one minute each side? If that.
Drain on paper towels.
For my giant family, I greased a 15x9 casserole. Put a smidge of your favorite tomato sauce in the bottom. Layer with cooked eggplant/zucchini. Top with cheese (I used sliced provolone; it's what I had, and I am a GENIUS for it). Continue layers, ending with a sauce layer. Then, because we are gluttonous and I only make this dish once a year, I topped it with more cheese. Parmesan this time.
Cover with foil and bake. I did mine at 350 for about 30-40 minutes.