
Caramelized onions and melted Gruyère are a heavenly match, so sandwiching them between crispy toasted bread is a sure win. This grilled cheese take on the classic French onion soup will make you wonder why you ever bothered with the broth.
The onions:
Caramelized onions aren’t difficult to make, but they can’t be rushed. Keep the burner turned to medium-low and stir every once in a while, scraping the bottom of the pan and adding a tablespoon of water if the onions start to stick. Don’t be tempted to hurry them by turning up the heat; the moment the onions start to sizzle aggressively, they’re frying, not caramelizing. They’ll definitely brown faster, but they won’t have that beautiful sweetness and luscious jammy texture. You can’t fast-track flavor.
The ratios:
A sandwich requires thoughtfully balanced ingredients and careful construction, and this French onion grilled cheese is no different. During development, I experimented with different ratios of bread, cheese, and onions, and found that pairing 1/4" slices of bread with 1 oz. Gruyère and 1/4 cup caramelized onions produced the ideal balance of flavor and texture for myself and taste-testers. Of course, taste is subjective, and if you prefer more cheese or a bigger pile of onions, it’s your sandwich. Go wild.
Storage:
Grilled cheese is always best fresh, but if you want to work ahead, the caramelized onions can be made up to three days in advance. Store in an airtight container in the refrigerator. Just make sure they come back to room temperature before you use them—if they’re cold, they’ll prevent the cheese from melting!
Made this? Let us know in the comments below.
Ingredients
Caramelized Onions
- 2 Tbsp.
unsalted butter
- 2
large yellow onions, thinly sliced into half-moons
- 1 tsp.
kosher salt
- 2
sprigs fresh thyme
- 1/3 cup
dry white wine
Sandwiches
- 8
(1/4"-thick) slices crusty country-style bread
- 4 Tbsp.
unsalted butter, softened
Freshly ground black pepper
- 2 tsp.
fresh thyme leaves
- 4 oz.
Gruyère, thinly sliced
Directions
Caramelized Onions
- Step 1In a large skillet over medium heat, melt butter. Add onions and salt and cook, stirring occasionally, until onions are jammy and deep golden brown, 35 to 50 minutes.
- Step 2Add thyme and wine and cook, stirring and scraping up bits from bottom of pan, until liquid is reduced and onions are jammy, 1 to 2 minutes. Let cool slightly.
- Step 3Make Ahead: Onions can be caramelized 3 days ahead. Let cool, then transfer to an airtight container and refrigerate. Return to room temperature before using.
Sandwiches
- Step 1On a clean surface, arrange bread slices in a single layer. Spread butter on top of each slice of bread. Flip 4 slices buttered side down, then top with caramelized onions; season with pepper. Sprinkle with thyme. Arrange 1 ounce Gruyère on top of onions. Close with remaining bread slices buttered side up.
- Step 2Preheat a large nonstick skillet over medium heat. Add 2 sandwiches, arranging cheese side closest to pan, and cook until golden brown, 2 to 3 minutes. Flip and continue to cook until golden brown on the other side and cheese is melty, 2 to 3 minutes more. Transfer sandwiches to a plate. Repeat with remaining sandwiches. Serve warm.