Preheat oven to 350°F (175°C) once the sauce is done.

Cut the zucchini lengthwise into quarters, then dice into 1/2 inch cubes.

Heat olive oil in a deep pan.

Sauté the onions and garlic until softened.

Add the zucchini cubes and cook until almost tender.

Puree the tomatoes.

Add the pureed tomatoes to the zucchini mixture, along with tomato sauce, tomato paste, and spices (basil, salt, garlic powder, onion powder, red pepper flakes, oregano, black pepper).

Cook the sauce for 45-60 minutes on medium heat, stirring occasionally.

Taste and adjust the seasonings to your preference.

Shred the mozzarella cheese and set aside.

Grate the parmesan cheese and set aside.

If using ricotta cheese, set aside.

In a lasagna pan, spread a thin layer of sauce on the bottom.

Place lasagna sheets over the sauce, cutting to fit the pan.

Layer 1/4 of the sauce over the lasagna sheets.

Sprinkle 1/4 of the parmesan cheese over the sauce.

Dollop 1/4 of the ricotta cheese (if using) over the parmesan cheese.

Top with 1/4 of the shredded mozzarella cheese.

Repeat the layering process three more times.

Bake for approximately 45 minutes, uncovered, until the dish is hot and the cheese is melted and bubbly.

Let the lasagna sit for 10 minutes before serving.