1. Squeeze spinach very dry to avoid a watery dip. For extra flavor add 1 tsp Worcestershire sauce or 2 tbsp chopped sun dried tomatoes. Swap Greek yogurt for sour cream for a lighter option. Use pepper jack or fontina in place of mozzarella for more punch. Make ahead by assembling and refrigerating up to 24 hours then bake as directed adding 3 to 5 minutes