I went to college in Wisconsin, so as you can imagine ... I love cheese! I love all kinds of cheese, but the combination of a good cheddar and mozzarella makes for the gooiest, meltiest grilled cheese. And who doesn't love dipping the classic sandwich in homemade tomato soup?
Technique tip: Adding Parmesan to the butter makes the crust salty and crispy.
In a large skillet, cook pancetta over medium heat until browned and crisp, flipping a few times to prevent burning. Remove from skillet and let cool on a paper towel. Save pan for sandwiches.
In a small bowl, stir together butter and Parmesan until combined. Spread the cheesy butter on one side of each slice of bread.
Place buttered-side slice of bread in skillet. Add two slices of cheddar and two slices of mozzarella, then top with another slice of bread (buttered-side up). Cook over medium heat for 5 to 7 minutes per side, until bread is golden and cheese is melted.