This Four Cheese Grilled Cheese Sandwich layers Cheddar, provolone, Swiss, and Colby-Jack between buttery slices of bread for a rich, melty upgrade to the classic. A sprinkle of green onion adds a fresh, savory twist that balances the indulgent filling. Toasted to golden perfection on a griddle, it’s a cozy, satisfying meal that’s easy to customize and perfect for sharing.