Spinach and Artichoke Pull-Apart Bread

Preheat oven to 350 degrees F. In medium bowl, thaw frozen spinach according to package's instructions. Turn spinach out onto kitchen towel and roll it up—then squeeze out excess water. Return to bowl. Chop artichoke hearts and add to spinach. Slice top of bread long-ways and then cross-ways, being careful not to cut loaf all the way through. Gently open cuts of loaf, and spread insides with mayonnaise. Fill cuts with spinach and artichoke mixture, tucking vegetables deeply into cuts. Sprinkle cuts with grated Parmesan and shredded mozzarella, making sure cheeses get into the cuts and coat the top of the loaf. Move loaf to sheet pan, and bake for 20 minutes, until cheese is melted. Serve immediately.