Caramelized Onion & Gruyère Grilled Cheese (Printable Page)

Sweet caramelized onions paired with nutty Gruyère cheese, melted between crispy golden country bread for an elegant comfort sandwich.

# 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

# Steps:

01 - In a large skillet over medium-low heat, melt butter with olive oil. Add sliced onions, salt, and pepper. Cook, stirring occasionally, until deeply golden and caramelized, approximately 25-30 minutes. Stir in thyme and balsamic vinegar, cooking 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. Place remaining bread slices on top to close sandwiches.
03 - Spread softened butter on the outside of each sandwich.
04 - Heat non-stick skillet or griddle over medium heat. Place sandwiches in pan and cook until golden brown and cheese is melted, approximately 3-4 minutes per side. Gently press with spatula to ensure even toasting.
05 - Slice sandwiches in half and serve immediately.

# Expert Advice:

01 -
  • The slow-cooked onions become impossibly sweet, creating this incredible depth that balances the nutty, slightly sharp Gruyère
  • Theres something deeply satisfying about taking humble ingredients and transforming them into something that feels fancy and indulgent
02 -
  • Resist the urge to crank up the heat when caramelizing onions—high heat makes them bitter and dry instead of sweet and jammy
  • Letting the sandwiches rest for just 30 seconds after grilling helps the cheese set slightly so it doesnt all ooze out when you cut them
03 -
  • Add a thin layer of Dijon mustard to the inside of the bread before assembling for a sharp contrast to the sweet onions
  • Comté or Emmental make excellent substitutes if you cant find Gruyère or want to experiment with different flavor profiles
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