Preparation Steps

• Make the meat sauce: In a large pot over medium heat, brown the ground beef. Drain excess fat. Add chopped onion and minced garlic, and cook until softened, about 5 minutes. Stir in crushed tomatoes, tomato paste, water, dried basil, dried oregano, salt, and black pepper. Bring to a simmer, then reduce heat and cook for at least 20 minutes, stirring occasionally. For a richer flavor, simmer longer.
• Make the béchamel sauce: In a medium saucepan, melt the butter over medium heat. Whisk in the flour until smooth. Gradually whisk in the warmed milk until the sauce is smooth and thickened. Season with salt and nutmeg.
• Prepare the cheese filling: In a medium bowl, combine ricotta cheese, egg, and grated Parmesan cheese. Mix well.
• Preheat oven to 375°F (190°C).
• Assemble the lasagna: Spread a thin layer of meat sauce on the bottom of a 9x13 inch baking dish. Arrange a layer of cooked lasagna noodles over the sauce. Spread half of the ricotta mixture evenly over the noodles. Spoon about one-third of the remaining meat sauce over the ricotta. Drizzle with about one-third of the béchamel sauce. Sprinkle with about one-third of the mozzarella cheese.
• Repeat the layers: Add another layer of noodles, the remaining ricotta mixture, half of the remaining meat sauce, half of the remaining béchamel sauce, and half of the remaining mozzarella cheese. Top with a final layer of noodles, the rest of the meat sauce, the rest of the béchamel sauce, and the rest of the mozzarella cheese.
• Bake for 25-30 minutes, or until the lasagna is bubbly and the cheese is golden brown. Let stand for 10-15 minutes before serving.