Cut the leeks in two lengthways and wash thoroughly.
Peel and chop the shallot.
Melt the butter in a frying pan and add the leeks and chopped shallot.
Cook over a medium flame for 20 minutes.
Add the cream at the end of this process and cook for a further 2 to 5 minutes. Season with salt and pepper.
Shell the prawns and cook them in a pan with one tablespoon of oil and 4 tablespoons of water.
Arrange the ingredients on plates in this order: the penne, the leek fondue, then the gambas.
Boil the water for the pasta and cook them “al dente” following the instructions on the pack.