Lasagnes de Mamie Praline

03 — Method

1. Peel the carrot, celery and onion and cut into very small even dice. Cut the 150 g (5 oz) pancetta into 5 mm (¼ in) dice too.Making it from scratch? See the fresh pasta — ≈ 30 min + repos
2. Heat 2 tablespoons olive oil in the large pot over medium heat. Add the pancetta and fry for 5 minutes until it renders its fat and turns golden.
3. Add the celery, carrot and onion and cook for 8 minutes over low heat, stirring, until tender and the onion is translucent.
4. Add the 300 g (10 oz) sausage meat, break it up with the spoon and cook for 5 minutes, stirring. Then add the 500 g (1 lb) ground beef and cook 5 minutes more, until no longer pink.
5. Deglaze with the 100 ml (scant ½ cup) red wine and let it evaporate for 3 minutes over high heat. Add the 800 g (28 oz) tomato purée and the bouquet garni, and season with salt and pepper. Cover and simmer for 1½ hours over very low heat.
6. Meanwhile, heat the 500 ml (2 cups) milk. In the small saucepan, melt the 35 g (2½ tbsp) butter over medium heat, add the 35 g (¼ cup) flour and whisk for 2 minutes to cook the roux.
7. Gradually pour the hot milk onto the roux, whisking constantly. Add the pinch of nutmeg and some salt, then let thicken for 5 minutes over low heat into a smooth béchamel that coats the spoon.
8. By the end of cooking, the meat sauce should have reduced, with three-quarters of its liquid evaporated. Remove the bouquet garni. Preheat the oven to 180 °C (350 °F) and lightly butter the baking dish.
9. Assemble the lasagna: a layer of sheets, a layer of meat sauce, a few tablespoons of béchamel. Repeat once more, then finish with a final layer of sheets.
10. Cover this last layer with a thick layer of béchamel — don't skimp: it protects the top sheets and keeps them from burning. Sprinkle with the 100 g (1 cup) grated Parmesan.
11. Bake for 40 to 45 minutes at 180 °C (350 °F), until golden on top and a knife slides through easily. Let rest 10 minutes before serving.