Prepare tagliatelle as per package instructions. Mine normally takes 6 minutes, but I always make sure I only cook it for 5 minutes.
While waiting for the pasta water to boil, melt butter in a medium to large pan, over medium high heat.
Add the asparagus and cook for around 2 minutes. Add the chanterelle and mix. Cook for 4 minutes.
Add crème fraiche and cook for 2 to 3 more minutes. Season with salt and pepper.
Add the cooked tagliatelle. Mix to combine and properly coat the pasta with the sauce. Take off the heat after a minute.