1. Preheat the oven to 375°F (190°C).
2. Slice the zucchinis lengthwise, lightly salt them, and let them rest for 10 to 15 minutes. Pat dry with a paper towel.
3. Heat olive oil in a skillet over medium heat and sauté the chopped onions and minced garlic until fragrant and translucent.
4. Stir in the marinara sauce, dried oregano, and dried basil, then let the mixture simmer for 5 to 7 minutes to combine the flavors.
5. In a mixing bowl, combine the cottage cheese, eggs, half of the shredded mozzarella, grated Parmesan, salt, and pepper until evenly mixed.
6. Grease a 9×13-inch baking dish and spread a thin layer of the marinara sauce on the bottom.
7. Layer the zucchini slices over the sauce, then spoon a layer of the cheese mixture on top. Repeat these layers, finishing with a final layer of sauce and the remaining mozzarella cheese.
8. Cover the dish with foil and bake for 25 minutes. Remove the foil and continue baking for another 15 to 20 minutes, or until the casserole is golden and bubbly.
9. Allow the dish to rest for 10 minutes before slicing. Garnish with fresh parsley or basil and serve.