Heat water in a sizable pot for pasta. Once boiling, add salt and pasta, and cook according to package. When done, strain the pasta and pour back into the pot.
Meanwhile, heat a medium-large pan on medium heat and add 2 T of the butter. Once butter is melted, toss in asparagus and garlic. Cook for 5 minutes. Then, cover pan with a lid and bring heat down to low. Steam asparagus for another 5 minutes, covered. Remove from heat and pour into the pot with the pasta.
Add the lemon zest (we're into this zester right now!), lemon juice, cheese, milk and the remaining 2 T butter to the pasta pot. Stir.
Then add prosciutto, tomatoes, and arugula to the pasta pot. Stir and season to taste with salt & pepper.
Serve with extra parmesan cheese sprinkled on top.
We recommend that all meals for children be served with milk.