HEAT oven to 350°F.
PROCESS spinach, Parmesan cheese, 2 Tbsp. nuts and garlic in food processor or blender until blended.
ADD oil in steady stream to spinach mixture through pour spout of food processor container, processing continuously until mixture is well blended. Spoon into 2- to 3-cup baking dish; stir in mozzarella cheese and remaining nuts.
BAKE 15 min., stirring after 8 min. Serve on crackers.