Melt the butter in a saucepan, add the flour and sweat while stirring. Gradually add the milk while stirring and simmer for about 20 minutes. Season with salt, pepper and nutmeg.
Cook the red lentils according to the instructions on the packet.
Chop the onions and garlic into small pieces. Fry the onions and garlic until translucent, then remove from the pan.
Cut the pumpkin and savoy cabbage into small pieces. Sauté the pumpkin and savoy cabbage in a pan, add the red lentils, onions and garlic and curry. Season to taste with salt and pepper.
In a baking dish, first layer vegetables, then bechamel and then lasagne sheets, crumble some feta between them. Finish with vegetables, bechamel and Gouda.