Steak Marsala with Cauliflower Mash

Name: Steak Marsala with Cauliflower Mash
Ingredients: 1 head cauliflower, cut into florets; 2 sprigs rosemary (leaves from 1 sprig chopped); Kosher salt; 1 1/2 cups shredded Italian cheese blend (about 5 ounces); 4 tablespoons unsalted butter; 2 tablespoons chopped fresh chives Freshly ground pepper; 4 beef eye-round steaks (1/2 inch thick; about 5 ounces each); 1 large shallot, chopped; 2 cloves garlic, chopped; 8 ounces sliced white mushrooms (about 4 cups); 1/2 cup sweet Marsala wine or white wine; 1/2 cup low-sodium chicken broth