Prep the Vegetables: Place sliced zucchini and onion in a colander. Sprinkle with a little salt and let sit for 20–30 minutes to release excess moisture. Gently squeeze out liquid with a clean towel or paper towels.

Make the Batter: In a large bowl, whisk together cornmeal, flour, baking powder, salt, pepper, and Parmesan. Stir in water and olive oil to form a loose, pancake-like batter.

Add the Veggies: Fold in the drained zucchini, onion, and basil until well combined.

Bake: Preheat oven to 400°F (200°C). Line a 9×13-inch baking pan or rimmed sheet with parchment and lightly oil it. Spread the batter evenly into a thin layer. Drizzle the top with a little more olive oil.

Roast Until Golden: Bake for 35–40 minutes until the edges are crispy and golden brown. For extra crispiness, broil for 2–3 minutes at the end.

Serve: Let cool slightly, then slice into squares or wedges. Serve warm or at room temperature as an appetizer, snack, or side dish.