01 - Preheat oven to 425°F (220°C). Arrange mozzarella sticks on a baking sheet and bake as directed on packaging, typically 8–10 minutes, until golden brown and crisp.
02 - While the mozzarella sticks bake, spread softened butter evenly on one side of each slice of bread.
03 - Heat a skillet over medium heat. Lay two bread slices, buttered side facing down, on the skillet. Top each with two slices of mozzarella cheese.
04 - Once mozzarella sticks are crisp, immediately place two hot sticks on top of the cheese on each sandwich. Add a light sprinkle of salt and pepper, as desired.
05 - Position the remaining bread slices over each sandwich, buttered side outward.
06 - Cook sandwiches for 2–3 minutes per side, gently pressing, until bread is golden and cheese is melty.
07 - Transfer sandwiches from skillet and let rest for 1–2 minutes before slicing in half.
08 - Serve immediately alongside warm marinara sauce for dipping.