Cook the tagliatelle according to the instructions and save some of the cooking water.
Meanwhile, grate the zest of the lemon in a small bowl and squeeze out the juice. Add 2 pressed garlic cloves and some ground pepper to the lemon. Mix everything together.
Wash the asparagus, cut off the ends and cut the rest into pieces about 2 cm in size.
Fry the asparagus pieces in a large pan with olive oil until they are lightly colored. Then add the prawns to the asparagus, fry them and season with sea salt and a little pepper (cayenne pepper or chilli if necessary). Now deglaze with the lemon and garlic mixture, fry briefly and then stir in the crème fraîche. Add the collected pasta water (about half a cup) until the desired consistency is reached. The sauce should still be slightly creamy.
Finally fold in the pasta and season with salt and pepper to taste. If you like, you can rub some parmesan on top.