French Onion Grilled Cheese

This French onion grilled cheese takes everything you love about the classic soup with deeply caramelized onions, nutty melted Gruyère, and a hint of balsamic, all layered between slices of crispy buttered country-style bread. Make the onions ahead, and the sandwiches come together in under 15 minutes.

Print Pin

Course: Sandwich, Side Dish

Cuisine: American

Keyword: caramelized onion grilled cheese, french onion grilled cheese

Prep Time: 10

Cook Time: 40

Total Time: 50

Servings: sandwiches

Calories: 653kcal

Author: Lyn Croyle

Ingredients

Caramelized Onions

1 tablespoon olive oil
1 tablespoon butter
1 large onion sliced thin (about 2-3 cups)
1 teaspoon sugar
¼ teaspoon salt plus more to taste if needed
1 tablespoon balsamic vinegar
¼ teaspoon dried thyme
1 small bay leaf or ½ large

Grilled Cheese

4 slices Country-style or ciabatta bread
2 tablespoons butter
1 cup grated Gruyere cheese Emmenthal or Comte are good substitutes
1 cup arugula
Balsamic vinegar syrup optional

Instructions

Make Caramelized Onions

Heat olive oil and butter in a saucepan over medium-low heat. Add onions, sugar, and salt. Cook for 18-20 minutes until onions soften and are beginning to brown.
Add balsamic vinegar, thyme, and bay leaf. Cook for another 8-10 minutes. Onions should be very soft and golden brown. Remove bay leaf. Taste and add more seasoning if needed. Transfer to a paper towel-lined plate to drain any excess butter and oil.

Assemble Sandwich

Butter one side of all slices of bread. Place upside down in cold pan or on a clean surface. Top half the slices with half the cheese. Add onion mixture on top, followed by arugula. Top with remaining cheese and then top with other slice of buttered bread with the butter side facing up.
Place skillet over medium heat and cook until they brown on one side. Flip and continue to cook until cheese is melted and both sides of bread are golden brown.

Nutrition