01 -
Grate the mozzarella and cheddar or gruyere cheese using a box grater if not pre-shredded.
02 -
Spread softened salted butter evenly on both sides of each slice of sourdough bread.
03 -
Preheat a heavy-based skillet or non-stick frying pan over medium-low heat and toast one side of each bread slice for 1 minute to start melting the cheese.
04 -
Flip one slice, then layer the shredded cheeses evenly on the toasted side. Place the second bread slice on top with the toasted side facing the cheese.
05 -
Press down lightly and cook the sandwich for 3 minutes over medium-low heat until the underside becomes deeply golden brown. Adjust heat if browning too quickly.
06 -
Carefully flip the sandwich and cook the other side for another 3 minutes until golden, crisp, and the cheese is fully melted.
07 -
Remove from heat, transfer to a cutting board, cut the sandwich in half, and serve immediately to enjoy the molten cheese pull.