Fusilli w/ Green Beans, Pancetta and parmigiano

kosher salt
1/2 lb. fusilli or other twisted pasta
4 oz. pancetta, cubed
1 large garlic clove, smashed and peeled
1 lb. green beans
freshly ground black pepper
2 Tbsp. butter, at room temperature
2 oz. Parmigiano-Reggiano, finely grated

1. Bring a medium pot of water to a boil.  Cook the pasta until just barely al dente, about 1 min less than package timing.  Reserve 1 C. cooking water and drain the pasta. 

2. While the pasta cooks, put the pancetta into a cold 10-inch skillet and set of medium-high heat.  When the pancetta starts sizzling, add the garlic and cook, stirring constantly until starting to brown, about 1 minute.  Reduce heat to medium and continue to cook the pancetta until golden but still chewy in the center, an additional 2-3 minutes.  If the pancetta has rendered a lot of fat, spoon off all but 1 Tbsp.  

3. Add the beans to the pan and cook, stirring constantly, until they're crisp-tender, 3-4 minutes.  Remove the garlic and season the beans with salt and pepper.  With the pan still over medium heat, add the pasta, 1/2 C. pasta water and the butter.  Toss to combine.  Add another 1/4 C. pasta water and 3/4 C. parmigiano.  Stir well and season to taste with salt and pepper.  If necessary, add a little more pasta water to loosen the sauce.

4. Serve with black pepper ground over top and sprinkled with remaining Parmigiano cheese.