Wash, halve and core the pumpkin. Peel the onions and garlic. Drain the pickled tomatoes and collect the oil. Dice everything ½ cm in size.
Heat 2 tablespoons of the collected tomato oil in a saucepan. Sauté the onions in it. Add the garlic. Then add the pumpkin and steam a little too. Deglaze with the chopped tomatoes and the stock, then season with salt and pepper. Cook the vegetables for about 15 minutes.
Prepare a bechamel sauce with the butter, flour, milk, the bay leaf, salt and pepper. Refine them with the remaining tomato oil.
Grease a baking dish and pour in some bechamel sauce. Layer alternately with lasagne sheets, vegetables and bechamel sauce. Sprinkle with the cheese.
Put in the oven and bake at 200 ° C for about 30-35 minutes.
Tip: You can pickle the tomatoes yourself the day before. The liquid from soaking the tomatoes can also be used for lasagne.