Classic Italian Meat & Vegetable Lasagna with Béchamel

Prepare the meat sauce: Heat 2 tablespoons of oil in a skillet over medium heat. Add the ground meat and fried onions, cooking until lightly browned. Pour in 1 cup of water and simmer until fully absorbed. Stir in the tomato paste, season with salt and black pepper, and cook for 2–3 minutes until well blended. Set aside.

Prepare the vegetable layer: In a separate pan, heat another 2 tablespoons of oil. Sauté the green and red bell peppers with fried onions until slightly softened. Stir in the tomato paste and 1 cup of water, bring to a gentle boil, then add the mushrooms. Season with salt and pepper and cook until the vegetables are tender and flavorful. Set aside.

Cook the lasagna noodles: Bring a large pot of salted water to a boil. Add a small amount of oil to prevent sticking and cook the noodles according to package instructions until al dente. Drain, briefly rinse with cold water, and lay flat on a clean towel.

Make the béchamel sauce: Melt the butter in a saucepan over medium heat. Add the flour and stir continuously for 1–2 minutes until smooth and lightly cooked. Gradually whisk in the milk, stirring constantly to prevent lumps. Cook until thickened, then season with salt and black pepper.

Assemble the lasagna: Preheat the oven to 350°F (175°C). Lightly grease a baking dish with the remaining oil. Arrange a layer of lasagna noodles on the bottom, followed by meat sauce, vegetable mixture, béchamel sauce, and grated cheese. Repeat the layers until all ingredients are used, finishing with a generous layer of cheese.

Bake and rest: Bake for 30 minutes, or until the cheese is melted and lightly golden. Remove from the oven and let rest for 10 minutes before slicing and serving.