Preheat your oven to 375°F (190°C). Lightly grease a 9×13‑inch baking dish with olive oil or nonstick spray to prevent sticking and make cleanup easier.

If using regular lasagna noodles, bring a large pot of salted water to a boil. Cook the noodles according to package directions, but stop 1–2 minutes before fully tender. Drain and lay them flat on a lightly oiled baking sheet or piece of foil so they don’t stick. If using no‑boil noodles, skip this step.

In a large skillet or Dutch oven, heat 1–2 tablespoons of olive oil over medium heat. Add the chopped onion and cook for 3–4 minutes until softened and translucent. Add the ground beef, breaking it up with a spatula, and cook until browned and no longer pink, about 6–8 minutes. Drain excess grease if needed.

Stir in the minced garlic and cook for 30–60 seconds, just until fragrant. Pour in about 4 cups of marinara or pasta sauce. Add Italian seasoning, red pepper flakes if using, sugar if needed, and a generous pinch of salt and black pepper. Simmer on low for 10–15 minutes, stirring occasionally. Taste and adjust seasoning so the sauce is full‑flavored; it will mellow once layered with noodles and cheese. Stir in fresh basil at the end, if using.

In a medium bowl, combine the cottage cheese, egg, grated Parmesan, chopped parsley, about 1/2 teaspoon salt, and 1/4 teaspoon black pepper. Stir until evenly mixed. For a smoother, ricotta‑like texture, blend the cottage cheese before mixing in the other ingredients.

Arrange the pot of meat sauce, the cottage cheese mixture, shredded mozzarella, optional spinach, and the noodles near your prepared baking dish to make layering quick and organized.

Spread about 1 cup of meat sauce in a thin, even layer over the bottom of the baking dish. Lay 3–4 lasagna noodles over the sauce, slightly overlapping as needed to completely cover the bottom, trimming to fit if necessary.

Spoon about one‑third of the cottage cheese mixture over the noodles and spread it gently to the edges. If using spinach, scatter a portion over the cottage cheese layer. Sprinkle about 1 cup of shredded mozzarella evenly over the top.

Add another 1–1 1/2 cups of meat sauce over the cheese layer, then another layer of noodles, another third of the cottage cheese mixture (and spinach, if using), and more mozzarella. Repeat once more with sauce, noodles, cottage cheese mixture, and mozzarella. For the top, finish with a final layer of noodles, the remaining meat sauce, and the remaining mozzarella plus extra Parmesan, if desired.

Cover the baking dish tightly with foil, tenting it slightly so it doesn’t stick to the cheese. Bake at 375°F (190°C) for 25–30 minutes. Covering the pan helps the noodles cook through, especially if using no‑boil noodles.

Remove the foil and bake for an additional 15–20 minutes, or until the cheese on top is melted, bubbly, and lightly golden in spots. For a deeper browned top, broil for 1–3 minutes at the end, watching closely to prevent burning.

Let the lasagna rest on the counter for 15–20 minutes before cutting to allow it to set for cleaner slices. Garnish with extra chopped parsley or basil before serving.