Preheat the oven to 200°C. Sauté the garlic and onions in a little olive oil, then add the mince and fry. Then add the remaining ingredients and let simmer for approx. 10 minutes.
For the Béchamel sauce, heat all ingredients in a small pan until the sauce thickens.
Grease the baking dish well with oil. Then layer lasagna noodles alternately with zucchini, cheese slices, and mince sauce. Spread the Béchamel sauce on the top layer and finally cover with cheese slices.