Preheat oven to 350 degrees F.
In a large bowl, combine mozzarella, ricotta, spinach, Parmesan, mayonnaise, garlic powder, and salt and mix until combined.
Spoon dip into an oven-proof skillet or pie pan and sprinkle with crushed red pepper flakes.
Bake until warmed through, bubbly, and golden, 25 to 30 minutes.
Arrange Party Potato Rolls on a baking sheet. Brush with olive oil or butter and sprinkle with 1 tablespoon Parmesan. Bake until golden, about 3-5 minutes.
Remove rolls from oven and arrange in a ring around the skillet dip or on a serving platter with the dip in the center.