Wash asparagus spears. Trim woody ends and peel the lower quarter of the thicker asparagus spears with a vegetable peeler to remove the fibrous skin. Chop diagonal into about 1/3-inch (1 cm) thick slices. Leave the tips whole, about 2-3 inches long (5-7 cm).

Cook the pasta in salted water according to the packaging instructions.

In the meantime, melt butter in a large pan over medium heat and sauté the chopped asparagus including tips, about 5 minutes. Add a bit of lemon zest and stir.

Drain pasta and set some of the cooking water aside. Let pasta sit in the colander while making the sauce.

Add creme fraiche, some lemon zest (keep some for topping the finished dish), and black pepper to the empty pasta pot. Heat until creme fraiche becomes liquid, while stirring.

Add 1 tablespoon pasta cooking water at a time, while stirring to get a nice luscious and creamy sauce. If you add too much water at once, the sauce could break. Now add grated parmesan and more pasta water if needed. The sauce should resemble heavy cream. Add salt to taste (often not necessary because parmesan and cooking water are salty).

Squeeze some lemon juice over the asparagus in the pan (about 2 teaspoons), then stir. Add the drained pasta and most of the asparagus pieces (not the tips) to the pot with the sauce and stir to combine.

Serve the pasta with the remaining asparagus, some lemon zest, parmesan, and black pepper. Enjoy!