Preheat the oven to 375°F (190°C). Lightly coat a 9-inch pie dish, preferably a glass Pyrex, with cooking spray.
Spread the softened cream cheese evenly across the bottom of the pie dish using a spatula or butter knife. The cream cheese may slide a bit, but it does not need to be perfect.
Sprinkle ¾ cup of the grated mozzarella cheese evenly over the cream cheese layer.
Add ½ cup of the finely grated parmesan cheese evenly on top of the mozzarella.
Distribute the pizza sauce over the cheese layer, using a spatula or knife to spread it evenly if necessary.
Sprinkle the remaining ¾ cup of mozzarella cheese over the pizza sauce.
Evenly distribute the remaining ½ cup of parmesan cheese on top.
Arrange the pepperoni slices evenly over the cheese layer.
Bake in the preheated oven for 20 to 25 minutes, or until the cheese is melted and the dip reaches your desired level of doneness (baked for 23 minutes is suggested). Allow the dip to cool slightly before serving.