Antonia's vegetarian lasagna

Ingredients for 6 servings:

• 1 onion(s), finely chopped
• 1 clove(s) garlic, finely chopped
• 750 g tomatoes
• 2 carrots, diced
• 2 stalk(s) celery, thinly sliced
• 700 g mushrooms, sliced
• 3 tbsp oil
• 1 tsp thyme
• 1 tsp tomato paste
• salt and pepper
• 70 g flour
• 750 ml milk
• 1 pinch of nutmeg
• 200 g mozzarella, diced
• 4 tbsp Parmesan, grated
• Butter, in flakes
• 12 lasagna sheets, without pre-cooking

Instructions

Working time approx. 20 minutes; Total time approx. 20 minutes

Sauté the onion, garlic, carrots, celery, and mushrooms in oil. Remove the stems from the tomatoes, puree, and add to the dish. Season with thyme, tomato paste, salt, and pepper, and simmer slightly. For the béchamel sauce, melt the remaining butter, add the flour, and stir in the milk. Season with nutmeg, salt, and pepper and simmer for about 10 minutes. Preheat oven to 180°C (350°F). Grease a lasagna dish. Alternate layers of pasta, vegetable sauce, béchamel, mozzarella, and ¾ of the Parmesan cheese in the dish. Finish with béchamel, Parmesan, and knobs of butter. Bake for about 45 minutes.