Scallop and Fennel Pasta in Lime Butter Sauce

Name: Scallop and Fennel Pasta in Lime Butter Sauce
Ingredients: 1 pound dry-packed scallops; 1 pound dried spaghetti; salt; 1 large fennel bulb, quartered & cored, then sliced lenghthwise into thin wedges; 2 medium shallots, diced (about 1/3-1/2 cup); 8 tablespoons unsalted butter, divided; freshly ground black pepper; 2 medium to large limes, one zested and juiced, and one cut into wedges; 1 & 1/2 teaspoons dijon mustard; 2-3 teaspoons minced fennel fronds; 1/4 cup coarsely chopped flat-leaf parsley