- 4 yellow onions, chopped
- 4 tablespoons olive oil
- 2 tablespoons sugar
- ¼ teaspoon salt
- ¼ teaspoon pepper
- 16 cloves garlic, minced
- 1 teaspoon crushed red pepper
- 8 tablespoons tomato paste
- 4, 28 ounce cans whole tomatoes
- 2.5 tablespoons oregano
- Salt and pepper to taste
- 64 ounces ricotta cheese
- 2 cups fresh basil
- 1 cup parmesan cheese
- 4 eggs
- ½ teaspoon black pepper
- 3 pounds spinach, steamed
- 18 strips lasagna noodles, uncooked
- 3 pounds spinach, steamed and drained well
- 32 ounces mozzarella, shredded
- Heat oil in a large stock pot over medium-high heat. Add onion, salt, pepper, and olive oil. Stir often for 10–12 minutes. Reduce the heat to medium and add garlic, red pepper, and tomato paste. Stir until combined.
- Add tomatoes and bring to a simmer. Once the sauce begins to simmer, sprinkle in oregano. Cook 20 minutes. Use a wooden spoon to break the whole tomatoes into smaller pieces. Add salt and pepper to taste. Remove from heat.
- While the sauce simmers, add half of the filling ingredients into a food processor. Pulse until combined. Repeat with remaining ingredients. Cover and refrigerate until ready to assemble lasagna.
- Spray the Fish Pan with oil. Spread 4 cups of the sauce in the bottom of the pan. Lay 6 uncooked lasagna noodles on top. Spread 3 cups of the filling over the noodles. Top with 2 cups of spinach and 8 ounces of cheese. Repeat twice. Add 16 ounces of cheese to the last layer.
- Grease aluminum foil and cover the pan. Bake at 375 degrees Fahrenheit for 45 minutes. Remove the aluminum foil and continue baking until the top has started to brown, 15-20 minutes. Let cool for 15 minutes before slicing.