In a small bowl, combine the softened butter, garlic powder, and Italian seasoning. Mix until well blended.
Take one slice of Italian bread and spread a generous layer of the garlic butter mixture on one side. On the unbuttered side, sprinkle half of the grated Parmesan cheese, followed by a layer of shredded mozzarella cheese. Add 4 to 5 slices of pepperoni on top, then sprinkle the remaining Parmesan cheese over the pepperoni. Finally, add another layer of mozzarella cheese and top with the second slice of bread. Spread the remaining garlic butter mixture on the outside of this slice.
Preheat your skillet over medium heat. Once hot, carefully place your assembled sandwich in the skillet. Cook for about 3-4 minutes or until the bottom is golden brown and crispy.
Using your spatula, carefully flip the sandwich over. Cook for another 3-4 minutes, pressing down gently to ensure even cooking.
Once golden and crispy, remove the sandwich from the skillet and let it cool for a minute before slicing it in half. Serve with warm pizza sauce or marinara sauce for dipping.
