Follow these simple steps to create your Savory Zucchini Casserole:

1. Preheat the Oven: Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking dish with olive oil.
2. Prepare Zucchini: Slice the zucchinis into thin rounds and set aside.
3. Mix Cheeses: In a large bowl, combine the ricotta cheese, cheddar cheese, and half of the Parmesan cheese. Mix well.
4. Add Eggs and Spices: Beat the eggs in a separate bowl, then add them to the cheese mixture. Stir in garlic powder, oregano, salt, and black pepper.
5. Layer Zucchini: Begin layering half of the sliced zucchini in the bottom of the greased baking dish.
6. Spread Cheese Mixture: Spoon half of the cheese mixture over the zucchini layer, spreading it evenly.
7. Repeat Layers: Layer the remaining zucchini slices on top, followed by the rest of the cheese mixture.
8. Top with Breadcrumbs: If desired, sprinkle breadcrumbs on top of the final layer for added crunch. Finish with the remaining Parmesan cheese.
9. Bake: Place the dish in the preheated oven and bake for 30-35 minutes, or until the top is golden and bubbly.
10. Cool Before Serving: Allow the casserole to cool for a few minutes before slicing and serving.