Hot Spinach and Crab Dip

Name: Hot Spinach and Crab Dip
Ingredients: 2 tablespoons unsalted butter; 1 small onion, finely chopped; 1 clove garlic, finely chopped; Kosher salt and freshly ground black pepper; 8 ounces cream cheese; 1 teaspoon Worcestershire; 1/2 teaspoon dry mustard; 1/2 teaspoon paprika; 1/8 teaspoon cayenne; 1 pound frozen chopped spinach, thawed and squeezed very dry; 8 ounces lump crabmeat, picked through for bits of shell; 1/2 cup shredded Monterey Jack; 3 tablespoons grated Parmesan; 2 tablespoons panko breadcrumbs; Crackers, for serving