Put the spaghetti to boil in salted water, according to the instructions on the package. When they are cooked, we drain them from the water and pass them through a stream of cold water.
Meanwhile, clean the leek and cut it into slices. I have to brag that I used the knife I won with your help, at the Recipe of the Year contest :), and I am very happy with it.
Heat the oil in a pan and add the leek slices.
Leave for a few minutes until soft then add 2 tablespoons of pesto and a pinch of water in which they cooked the pasta. Let it boil until the water drops.
Then add the pasta and the drained peas and mix until smooth. Season with salt and pepper and serve hot.