Prepare the meat sauce

• Heat the olive oil in a frying pan and soften the onion and garlic.
• Add the ground beef and brown it well.
• Pour in the tomato passata, season with salt and pepper and simmer.

Make the béchamel

• Melt the butter in a saucepan.
• Stir in the flour and cook briefly.
• Whisk in the milk gradually and cook until thickened, then season with salt and pepper.

Layer the lasagna

• Spread a little meat sauce in the baking dish.
• Alternate lasagna sheets, meat sauce, béchamel and parmesan.
• Finish with béchamel, mozzarella and parmesan.

Bake the lasagna

• Bake in the oven at 180 °C until golden and bubbling.
• Let it rest before serving.