Cut the woody ends of the asparagus and cut them in 2 inch pieces.
Bring water and salt in a pan to a boil.
Heat a tablespoon of butter in a skillet and add the asparagus. Cook them on high heat for approx. 3 minutes, so they blacken a little. (NOTE 1)
Once cooked, transfer the asparagus to a place and set aside.
Add another tablespoon of butter to the skillet, add the cream, nutmeg, cayenne pepper, and rosemary. Whisk in the grated Parmesan cheese and simmer for a few minutes. The sauce becomes a little thicker.
Add the gnocchi to the boiling water, cook for about a minute and the gnocchi will come to the surface. Drain them and add them to the sauce.
Add asparagus and arugula to the sauce and taste. Add salt and pepper if needed.
Notes
If you don't like blackened asparagus, cook them a little longer on medium high heat. Don't cook them all the way through, you want to keep them crunchy. You can also cook them in the oven, by sprinkling them with oil, place them on a baking sheet and cook at 425 degrees F for approx. 15 minutes (depending on how cooked you like them to be).