Preheat oven to 350 degrees. Spray a 3 or 4 cup baking dish with nonstick cooking spray.
Squeeze spinach to remove liquid. In a medium bowl combine spinach, mayonnaise, cream cheese, onion, garlic, parmesan cheese and pepper. With hand mixer, beat ingredients at medium speed until well blended, about one minute.
Spoon the mixture into baking dish. Sprinkle with paprika. Bake at 350 degrees until hot in center and lightly browned on top, about 30 minutes. Serve hot to spread on crackers or baguette slices.