Lasagne al forno

Prepare the beef ragu: Finely chop the onion, carrot, and celery. Heat the olive oil in a large pot over medium heat. Add the chopped vegetables and sauté for 5-7 minutes until softened. Add the ground beef and brown it, breaking it up with a spoon, for about 8-10 minutes. Stir in the tomato passata, 0.75 tsp salt, and 0.4 tsp black pepper. Bring to a simmer, then reduce heat to low, cover, and let it cook for at least 35 minutes, stirring occasionally.

Prepare the béchamel sauce: In a separate saucepan, melt the butter over medium heat. Add the flour and whisk continuously for 1-2 minutes to form a roux. Gradually pour in the milk, whisking constantly to prevent lumps. Continue to cook, whisking, until the sauce thickens to your desired consistency (about 10-12 minutes). Season with the remaining 0.25 tsp salt and 0.1 tsp black pepper.

Preheat your oven to 180°C (350°F) conventional heat. Lightly grease a large baking dish (approx. 20x30 cm).

Assemble the lasagne: Spread a thin layer of béchamel sauce at the bottom of the prepared baking dish. Place a layer of dry lasagne sheets over the béchamel. Top with a generous layer of beef ragu, followed by another layer of béchamel and a sprinkle of Parmesan cheese. Repeat the layers: pasta, ragu, béchamel, Parmesan, until all ingredients are used, finishing with a final layer of béchamel and a generous amount of Parmesan cheese on top.

Bake the lasagne: Cover the baking dish loosely with aluminum foil and bake for 20 minutes. Then remove the foil and bake for an additional 10 minutes, or until the top is golden brown and bubbly. Let the lasagne rest for 5 minutes before slicing and serving.