Caramelized Onion & Gruyère Grilled Cheese (Printable)

Gourmet grilled cheese featuring slow-cooked caramelized onions and nutty Gruyère cheese melted between crispy country bread.

# What You Need:

→ Caramelized Onions

01 - 2 large yellow onions, thinly sliced
02 - 2 tablespoons unsalted butter
03 - 1 tablespoon olive oil
04 - 1/2 teaspoon salt
05 - 1/4 teaspoon freshly ground black pepper
06 - 1 teaspoon fresh thyme leaves
07 - 1 teaspoon balsamic vinegar

→ Sandwiches

08 - 4 slices rustic country bread
09 - 4 ounces Gruyère cheese, grated
10 - 1 tablespoon unsalted butter, softened

# How-To Steps:

01 - In a large skillet over medium-low heat, melt 2 tablespoons butter with 1 tablespoon olive oil. Add sliced onions, salt, and pepper. Cook, stirring occasionally, for 25 to 30 minutes until deeply golden and caramelized. Stir in thyme and balsamic vinegar, then cook 1 minute longer. Remove from heat.
02 - Lay out bread slices. Evenly distribute caramelized onions on two slices. Top each with half of the grated Gruyère cheese. Place remaining bread slices on top to close the sandwiches.
03 - Spread softened butter evenly on the outside of each sandwich.
04 - Heat a non-stick skillet or griddle over medium heat. Place sandwiches in the pan and cook for 3 to 4 minutes per side until golden brown and cheese is melted. Press gently with a spatula to ensure even toasting.
05 - Slice sandwiches in half and serve immediately.

# Expert Suggestions:

01 -
  • The balsamic vinegar sneaks in a sweet tang that makes people ask what you did differently
  • Rustic bread creates a sturdy foundation that will not collapse when you bite down
  • These onions keep in the fridge for days, making your next sandwich even faster to assemble
02 -
  • Low and slow is nonnegotiable for the onions, or they will burn instead of caramelize
  • Grating the cheese yourself helps it melt more evenly than pre shredded options
  • Letting the sandwich rest for one minute after cutting keeps the cheese from oozing out immediately
03 -
  • Use a cast iron skillet if you have one for the most even browning
  • Grate the cheese while the onions cook to save yourself time later
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