Methods

TO PREPARE FAVA BEANS 

Fresh fava beans are one of spring’s true delectables, made more so by the fact tha they are truly seasonal; unlike so many vegetables that are grown commercially almost year-round, favas show up in stores and at farmers’ markets only in spring. Also called broad beans, favas do require a bit of prep. You’ll buy favas in their pods, and they look like overgrown, puffy green beans. Inside the pods are individual beans (four or five to a pod), each of which is encased in a tough membrane that needs to be removed. The final prize is a very tender, bright-green bean that splits into two halves. You’ll need about 2 pounds (900 g) of pods to yield 1 cup
(140 g) of peeled beans. Note that some cuisines use dried fava beans, which are not a substitute for fresh.

To prepare fresh fava beans: Bring a medium pot of water to a boil. Split open the fava pods and pop out the beans. Add the beans to the boiling water, cook for about 30 seconds, and then drain immediately. Rinse well with cold water to stop the cooking. Cut a small slit in the whitish membrane of each bean with the tip of a paring knife or your thumbnail, then gently squeeze out the two halves of the bright-green fava.

FOR THE PASTA 

1. Prepare the fava beans following the method above. Set aside.
2. Fill a large pot (at least 6 quarts/L) with 1 gallon (4 L) of water; add 4 tablespoons (40 g) kosher salt, cover the pot, and bring the water to a boil while you make your sauce. If the water begins to boil before your sauce is ready, turn down the heat, but don’t let the volume of the pasta water reduce by boiling off.
3. Heat a glug of olive oil in a large skillet over medium heat. When the oil is hot, add the prosciutto and cook gently to render the fat and crisp up the meat, 2 to 3 minutes. Season the prosciutto with several twists of black pepper.
4. Add the favas, cream, and 1/2 cup (120 ml) of water from the pasta pot to the skillet, reduce the heat to low, and gently simmer until the creamy mixture has reduced by about one-third, 3 to 4 minutes. Taste and add more salt and black pepper if you like. Slide the skillet off the heat.
5. Bring the pasta water (back) to a boil, add the noodles, and set your timer for 2 minutes less than the shortest suggested cooking time on the package of pasta; this will ideally be 2 minutes before the pasta is al dente. Stir the noodles several times during the first 2 minutes of cooking to prevent them from sticking to the pot or otherwise clumping together. 
6. When the timer goes off, start tasting the noodles. When they seem like they are almost a perfect al dente, drain and transfer them to the sauce using your preferred method, making sure to reserve 1 cup (240 ml) of the pasta water.
7. Slide the skillet back onto medium heat and finish cooking the noodles, tossing and adding plenty of splashes of pasta water until the noodles are perfectly al dente and the sauce is nicely juicy. If the sauce seems watery, simmer for another few seconds to tighten it up, bearing in mind that the cheese will thicken it.
8. Take the skillet off the heat and add the lemon zest and butter. Tear the mint leaves into a few pieces and add them.
9. Add the grated cheese and toss to emulsify it with the other sauce ingredients, adding splashes of pasta water (or plain hot water, if things are getting too salty) if needed to prevent the cheese from clumping.
10. Divide the pasta between two warm bowls and serve, with more cheese to add at the table.