Make the Meat Sauce
Heat the olive oil in a large skillet over medium-high heat.
Add the ground beef and cook until browned with crispy crumbles.
Stir in the diced onion and cook until softened and translucent.
Add the minced garlic and cook for 30 seconds until fragrant.
Stir in the tomato paste and cook for 2 minutes.
Pour in the crushed tomatoes and season with salt and pepper.
Simmer for 20 minutes, stirring occasionally, until thick and flavorful.
Prepare the Ricotta Mixture
In a medium bowl, combine the ricotta cheese, egg, half of the Parmesan cheese, salt, and pepper.
Mix until smooth and creamy.
Cook the Lasagna Noodles
Bring a large pot of salted water to a boil.
Cook the lasagna noodles for 2 minutes less than the package directions.
Drain and pat dry.
Assemble the Lasagna
Preheat the oven to 375°F (190°C).
Spread a thin layer of meat sauce across the bottom of a 9×13-inch baking dish.
Arrange a layer of lasagna noodles over the sauce.
Spread half of the ricotta mixture evenly over the noodles.
Add a layer of meat sauce followed by a generous handful of mozzarella cheese.
Repeat the layers: noodles, ricotta mixture, meat sauce, and mozzarella.
Finish with a final layer of noodles.
Top with the remaining meat sauce.
Sprinkle the remaining mozzarella and Parmesan cheese evenly over the top.
Bake
Cover the dish tightly with lightly greased aluminum foil.
Bake for 35 minutes.
Remove the foil and continue baking for 15 minutes.
Broil for 2–3 minutes until the cheese develops a golden-brown crust with crispy edges.
Rest and Serve
Remove the lasagna from the oven and let it rest for 20 minutes.
Garnish with chopped fresh parsley and a sprinkle of red pepper flakes.
Slice and serve warm.