Garganelli with Speck, Peas, and Scallion Cream

Prep Time: 5 mins Cook Time: 25 mins
Servings: 4
Ingredients
6 medium garlic cloves, divided
4 cups chopped scallions, green parts only (from 4 bunches)
3/4 cup heavy cream
1/4 teaspoon kosher salt
12 ounces uncooked bronze-cut garganelli pasta
1/4 cup cold unsalted butter (2 ounces), cut into 1/2-inch pieces, divided
1 1/2 cups sweet peas (6 ounces)
2 ounces thinly sliced speck (about 8 slices), torn into 2-inch strips
1 ounce Parmigiano-Reggiano cheese, grated with a Microplane grater (about 2/3 cup)