In a large bowl, beat together the cream cheese, mayonnaise and sour cream with a hand mixer until smooth.
Stir in the 3/4 cup pepper jack, 3/4 cup cheddar, parmesan, onion, garlic, worcestershire, garlic powder, onion powder, cayenne, lemon juice, salt and pepper until thoroughly combined.
Fold in the spinach. Transfer to a small baking dish and sprinkle the top with the remaining cheese.
Bake in the oven for 20-25 minutes until golden brown and bubbling.
Serve hot with crackers, crostini or vegetables.
Notes
Spinach Dip can be assembled up to 48 hours in advance. Wrap tightly with plastic wrap and store in the refrigerator until ready to bake.