Turn on the oven on 200°C. Cut the mushrooms, the courgettes and the carrots and then cook them in a pan with salt and olive oil.
When cooked, put the spinach in the pan, wait a few seconds and then put the tomato sauce and mix it all.
Place one lasagna sheet in a canister, put a layer of the vegetables and repeat until you have no more mixture. Pour the creme fraiche and on top put the mozzarella cheese and the tomatos cut in halves. Put in the oven for 40 minutes at 180°C