Peel, wash and thinly slice the carrots. Cook in boiling salted water for 8-10 minutes, drain and drain. Drain the corn. Let the peas thaw a little. Melt the fat in a pot.
Sweat flour in it. Deglaze with milk and stock while stirring. Add half of the cheese. Season to taste with salt, pepper and nutmeg. Put a thin layer of béchamel sauce in an ovenproof casserole dish. Place 6 lasagne plates on top. Spread peas over it, add some more sauce. Layer corn and carrots alternately with sauce and lasagne sheets. Finish the last layer with lasagne plates and the remaining béchamel sauce. Sprinkle the rest of the cheese on top.
Place 6 lasagne plates on top. Spread peas over it, add some more sauce. Layer corn and carrots alternately with sauce and lasagne sheets. Finish the last layer with lasagne plates and the remaining béchamel sauce. Sprinkle the rest of the cheese on top. Bake the vegetable lasagne in a preheated oven (electric: 200 °C/ gas: level 3) for 40-45 minutes. Cut the lasagne into 6 pieces and serve