For the macaroni lasagna preheat oven to 180°C.
Finely chop the onion, crush the garlic and grate the carrots. Sauté everything briefly in rapeseed oil, add minced meat and fry. Strain the canned tomatoes, add to the meat mixture, season with oregano, basil, salt and pepper, cover and simmer on low heat for about 10 minutes.
Meanwhile, cook the macaroni in boiling, lightly salted water uncovered for about 10 minutes.
For the sauce, dry roast whole wheat flour in a saucepan until light brown, pour in skim milk and season with salt and pepper.
In a coated round baking dish, alternate layers of macaroni and tomato sauce, pour the white sauce over everything and sprinkle with grated mozzarella.
Bake in the preheated oven for about 30 minutes.