Roll of courgette with leek and carrots

Heat 3 dl water in a pan. Cut slices of 3 mm thickness on the mandoline or with a knife. Marinate in oil and vinegar for 20 minutes. Cut the white of the leek in fine julienne, length about 5 cm. Put the rest of the leek in the water for the vegetable stock. Wash the carrots and clean them, also put the remaining in the water. Cut an onion in quarters and put into the stock, together with mace and laurel. Blanche the carrots for 8 minutes in the stock and put them into iced water. Put butter in a wide pan, a few spoons of butter and heat. When warm, put the leeks into the pan and let is stove under a piece of baking paper for 30 minutes. At the end, cover with a little sugar to caramelize. Put butter in a frypan together with garlic and thyme. Bake the carrots brown and crispy. Put aside. Take the slices courgette , dry with paper and blanche in the stock for a few minutes. Taken them out and cool down in iced water. Just before service: heat up the carrots in the frypan. Spread the slices courgette and put on them a carrot and some leek. Roll and serve. Set the sock aside and keep to use on another occasion.