1. Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish with olive oil.
2. In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes. Add the minced garlic and cook for another 1-2 minutes until fragrant. Remove from heat and set aside.
3. Place the thinly sliced zucchini in a colander, sprinkle with a pinch of salt, and let it sit for 10 minutes to draw out excess moisture. Then, gently squeeze the zucchini slices with your hands or a clean kitchen towel to remove any remaining water. This step is key to preventing a watery casserole, a trick I learned early on from Nonna Rosa herself.
4. In a large mixing bowl, combine the ricotta cheese, mayonnaise (or Greek yogurt), eggs, sautéed onion and garlic, chopped basil, oregano, crushed red pepper flakes (if using), salt, and pepper. Stir until smooth and well combined.
5. Fold in half of the shredded mozzarella and Parmesan cheese into the mixture.
6. Gently fold in the zucchini slices, ensuring they are evenly coated with the cheese mixture.
7. Pour the mixture into the prepared baking dish and spread it out evenly with a spatula.
8. Sprinkle the remaining mozzarella and Parmesan cheese evenly over the top. If you like a crispy topping, this is the moment to add the breadcrumbs.
9. Bake uncovered for 35-40 minutes, or until the top is golden brown and the casserole is bubbling around the edges.
10. Remove from the oven and let it rest for about 10 minutes before serving. This helps the casserole set and makes it easier to slice.

One of my favorite memories is watching Olivia and Isabella eagerly waiting for this cooling period, already planning how they’d sneak extra bites before dinner officially starts. It’s a dish that invites anticipation and togetherness.