Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish with cooking spray or a thin film of olive oil to help prevent sticking and make clean-up easier.

Bring a large pot of salted water to a boil. Add the lasagna noodles and cook until just under al dente, usually 1–2 minutes less than the package suggests. Drain, then lay the noodles flat on a lightly oiled baking sheet or parchment so they don’t stick. Drizzle with a little olive oil if needed.

Heat the olive oil in a large skillet or Dutch oven over medium heat. Add the chopped onion and cook for 3–4 minutes, until softened and translucent. Stir in the minced garlic and cook for another 30 seconds, just until fragrant. Add the ground beef, breaking it up with a wooden spoon. Season with kosher salt, black pepper, Italian seasoning, and red pepper flakes if using. Cook until the meat is no longer pink, about 6–8 minutes, then drain off any excess fat. Pour in the jar of marinara and the tomato sauce. Stir to combine and let simmer on low for 5–10 minutes, until thick but spoonable.

In a medium bowl, lightly whisk the egg. Add the cottage cheese, 1/2 cup grated Parmesan, dried parsley, garlic powder, salt, and black pepper. Stir until everything is evenly combined. The mixture should be creamy but scoopable.

Spread about 1 cup of the meat sauce in the bottom of the prepared 9×13-inch pan. Place a layer of noodles over the sauce, slightly overlapping. Spoon half of the cottage cheese mixture over the noodles and spread gently with a spatula. Sprinkle about 1 cup of shredded mozzarella over the cottage cheese layer.

Add another layer of meat sauce (about 1½ cups), then another layer of noodles. Spread the remaining cottage cheese mixture over the noodles and top with another cup of mozzarella.

Top with a final layer of noodles, then spread the remaining meat sauce evenly over the top. Sprinkle with the remaining mozzarella and 1/4–1/2 cup extra grated Parmesan. The lasagna should finish with sauce and cheese on top.

Cover the baking dish tightly with aluminum foil, tenting it slightly so it doesn’t stick to the cheese. Bake at 375°F (190°C) for 25 minutes. Remove the foil and bake for an additional 15–20 minutes, or until the lasagna is bubbling around the edges and the cheese on top is melted and lightly golden.

Let the lasagna rest for at least 15–20 minutes before slicing to allow the layers to set. Cut into squares with a sharp knife and lift out with a large spatula. Serve warm, optionally with a green salad and garlic bread.