Step 1: Prepare the zucchini. Using a mandoline or a very sharp knife, slice the zucchinis lengthwise into 1/8-inch thick strips. Lay the slices in a single layer on paper towels and sprinkle generously with salt. Let them sit for 15-20 minutes to draw out excess moisture. This is a crucial step for preventing a watery lasagna.
Step 2: While the zucchini rests, prepare the marinara sauce. Heat olive oil in a medium saucepan over medium heat. Add the chopped onion and cook until softened, about 5-7 minutes. Add the minced garlic and cook for another minute until fragrant. Pour in the marinara sauce, bring to a simmer, then reduce heat to low and let it gently simmer while you prepare the other components. Season with salt and pepper to taste.
Step 3: Prepare the ricotta mixture. In a medium bowl, combine the ricotta cheese, egg, 1/2 cup Parmesan cheese, chopped fresh parsley, and black pepper. Stir until well combined. Taste and adjust seasoning if needed.
Step 4: Blot the zucchini. After 15-20 minutes, gently blot the zucchini slices dry with fresh paper towels. This removes the salt and the released moisture. You’ll be surprised how much water comes out!
Step 5: Preheat oven and prepare baking dish. Preheat your oven to 375°F (190°C). Lightly grease a 9×13 inch baking dish.
Step 6: Assemble the lasagna. Spread about 1/2 cup of marinara sauce on the bottom of the prepared baking dish. Arrange a single layer of zucchini slices over the sauce, slightly overlapping. Spread half of the ricotta mixture evenly over the zucchini. Top with about 1/3 of the shredded mozzarella cheese. Spoon another 1/2 cup of marinara sauce over the mozzarella.
Step 7: Continue layering. Repeat the layering process: zucchini slices, the remaining half of the ricotta mixture, another 1/3 of the mozzarella, and another 1/2 cup of marinara sauce.
Step 8: Final layer. Place a final layer of zucchini slices on top. Cover with the remaining marinara sauce and sprinkle with the remaining mozzarella cheese and a little extra Parmesan.
Step 9: Bake the lasagna. Cover the baking dish tightly with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 15 minutes, or until the cheese is bubbly and lightly golden brown. If you like it extra golden, you can broil for a minute or two, watching carefully to prevent burning.
Step 10: Rest and serve. Let the lasagna rest for 10-15 minutes before slicing and serving. This allows it to set, making it easier to cut clean pieces. Garnish with fresh basil, if desired, and enjoy your delicious zucchini lasagna recipe!