Caramelized Onion Gruyère Cheese (Print)

Golden bread with melted Gruyère and deeply caramelized onions, offering a rich and savory twist.

# Components:

→ 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 granulated 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

# Directions:

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

# Chef Secrets:

01 -
  • Those onions cook while you do other things, filling your kitchen with the smell of slow caramelization that actually makes you hungry.
  • It tastes fancy enough to serve guests but takes no special skills, just patience and butter.
  • Once you taste Gruyère melted with caramelized onions, regular grilled cheese will feel incomplete.
02 -
  • Do not rush the onions—I learned this by trying to speed things up with high heat and ending up with onions that were burnt on the outside and raw inside. Medium-low heat means you can walk away and check on them without babysitting.
  • Spread butter on the bread before assembly so it cooks evenly and turns golden, not pale; this is what makes the outside properly crispy and not just oiled.
03 -
  • If your bread is browning faster than the cheese is melting, reduce the heat and cover the skillet with a lid or foil for the last minute to trap steam and help the cheese catch up.
  • Make your caramelized onions ahead of time—they keep for up to five days in the refrigerator and actually taste even better the next day as flavors settle and deepen.
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