Caramelized Onion Gruyère Cheese (Printer View)

Golden bread layered with caramelized onions and melting nutty Gruyère for a rich, savory bite.

# What You'll Need:

→ Caramelized Onions

01 - 2 medium yellow onions, thinly sliced
02 - 2 tablespoons unsalted butter
03 - 1/2 teaspoon kosher salt
04 - 1/4 teaspoon freshly ground black pepper
05 - 1/2 teaspoon sugar (optional)
06 - 1 teaspoon balsamic vinegar (optional)

→ Sandwich

07 - 4 slices rustic sourdough or country bread
08 - 2 tablespoons unsalted butter, softened
09 - 5 ounces Gruyère cheese, grated
10 - Caramelized onions prepared above

# Method Steps:

01 - Melt 2 tablespoons of butter in a large skillet over medium-low heat. Add the sliced onions, salt, and pepper. Cook, stirring occasionally, for 25 to 30 minutes until the onions are deeply golden and caramelized. Stir in sugar and balsamic vinegar if using, and cook for an additional 2 to 3 minutes. Remove from heat.
02 - Spread softened butter on one side of each bread slice. Place two slices butter-side down on a work surface. Evenly distribute half of the grated Gruyère over these slices. Spoon caramelized onions on top, then sprinkle the remaining Gruyère. Close each sandwich with the remaining bread slices, butter-side up.
03 - Heat a nonstick skillet or griddle over medium heat. Place the sandwiches in the skillet, cooking for 3 to 4 minutes per side while pressing gently, until the bread is golden brown and the cheese melts. Lower the heat if the bread browns too quickly.
04 - Slice the sandwiches and serve immediately.

# Expert Advice:

01 -
  • The caramelized onions turn sweet and jammy, making you forget you're eating something simple.
  • Gruyère has this nutty depth that transforms the whole sandwich into something restaurant-worthy.
  • It's proof that patience in the kitchen pays off without requiring any real skill.
02 -
  • Medium-low heat is non-negotiable for caramelizing onions—turning it up will give you burned onions with raw insides, which tastes bitter and ruins everything.
  • Don't be tempted to skip the balsamic vinegar if you have it; it adds a subtle depth that makes people taste something they can't quite name.
03 -
  • If your bread is browning too fast before the cheese melts, lower the heat slightly—the inside needs time to catch up with the outside.
  • Caramelized onions make an excellent addition to soups, salads, and even grain bowls, so don't hesitate to make extra and keep them in the fridge for a few days.
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