Preheat oven to 350 degrees F (175 degrees C). Spray a baking sheet with non-stick cooking spray.
Heat olive oil in a skillet or frying pan over medium heat. Add garlic and saute until soft, about two minutes. Add spinach and cook until liquid has evaporated. Stir in salt, pepper, Parmesan and garlic powder. Remove from heat and let cool.
On a lightly floured surface, roll out pizza crust into a 10x14 inch rectangle. Spread spinach mixture and mozzarella cheese on top of dough. Starting from on end, roll up the crust to make one large loaf. Pinch seam to seal. Place loaf onto prepared baking sheet.
Bake in preheated oven for 20 to 25 minutes, until golden brown.