Prepare the Bread:
Spread butter on one side of each slice of bread. This will be the outer side that gets grilled.

Assemble the Sandwiches:
On the unbuttered side of two slices of bread, spread a thin layer of marinara sauce. Layer mozzarella and cheddar cheese, then top with sliced pepperoni. Sprinkle oregano and garlic powder over the pepperoni.

Grill the Sandwiches:
Place the second slice of bread on top, buttered side facing outward. Heat a skillet over medium heat and cook the sandwiches for 3-4 minutes per side, pressing gently with a spatula, until the bread is golden brown and the cheese has melted.

Serve:
Remove the sandwiches from the skillet and let them rest for a minute before slicing. Serve warm and enjoy your Pepperoni Pizza Grilled Cheese!