Boil the paste according to the instructions on the package.
While it is cooking, fry the shrimps in warmed-up olive oil, while adding salt and pepper.
Add the leek rings and butter to the skillet. Stir, fry for 3 minutes, then pour in the cream. After a couple of minutes, when the cream thickens a little, remove the sauce from the heat.
Combine the prepared pasta with the sauce and serve.