Finely chop onion and garlic, sauté in olive oil.
Add minced meat and fry well. Add tomatoes with liquid, season with salt, pepper and thyme and simmer on low heat for at least 30 minutes. The sauce should be viscous.
For the béchamel sauce, melt the butter, add the flour and sweat. Gradually add milk or clear soup and cook well so that the flour taste disappears. Season with spices and fold in whipped cream.
Grease a gratin dish and pour in a thin layer of minced meat sauce. Place a layer of zucchini slices cut lengthwise into 5mm on top. Continue in this way until the zucchini and sauce are used up. Pour the béchamel sauce over the casserole and top the whole with sliced mozarella. Bake at 190 °C for 35 to 45 min until the whole is bubbling and the cheese has a nice color. Serve with baguette and a dry red wine.
Tip: Cook only with high-quality spices – they are the be-all and end-all in a good dish!