Generously butter each slice of bread, covering every corner.
Assemble the Sandwich:
Layer cheddar, mozzarella, and brie on one slice of bread.
Add optional caramelized onions or a drizzle of honey for extra flavor.
Top with the second slice of bread, butter side out.
Cook the Grilled Cheese:
Heat a skillet over medium heat.
Place the sandwich in the pan and cook 3–4 minutes per side, pressing gently with a spatula to ensure even browning.
Flip carefully and continue cooking until the bread is golden and crispy and the cheese is fully melted.
Serve:
Slice in half and serve warm. Pair with tomato soup or tangy pickles for a classic combination.
