Spinach Artichoke Dip

1 can (14 oz) artichoke hearts, drained, finely chopped
1 pkg (10 oz) frozen spinach, thawed, drained
3/4 c grated parmesan cheese
3/4 c mayo (NOT miracle whip)
1/2 c mozzarella cheese
1/2 t garlic powder

Mix all ingredients until well blended.  Bake in 9 inch pie plate or shallow baking dish for 20 min at 350.