Simple Linguine with Cauliflower and Prosciutto

Name: Simple Linguine with Cauliflower and Prosciutto
Ingredients: Kosher salt; 2 oz. 4 Tbs. unsalted butter; 2 Tbs. extra-virgin olive oil; 1 small head cauliflower about 1-1/2 lb., cut into 1-1/2-inch florets and halved lengthwise (about 5 cups); 12 oz. linguine; 6 anchovy fillets rinsed well, patted dry, and finely chopped (about 1 Tbs.); 1 Tbs. finely chopped fresh rosemary; 2 medium cloves garlic finely chopped; ¼ tsp. crushed red pepper flakes; 2/3 cup lower-salt chicken broth; 6 thin slices prosciutto or speck cut crosswise into ¼-inch strips; ½ oz. finely grated Parmigiano-Reggiano 1/2 cup; 1 Tbs. chopped fresh flat-leaf parsley