French Onion Grilled Cheese (Printable Version)

Caramelized onions with Gruyère and Provolone tucked in golden, crispy bread for a cozy meal.

# Everything You’ll Need:

→ Caramelized Onions

01 - 2 tablespoons unsalted butter
02 - 1 tablespoon extra virgin olive oil
03 - 1 large yellow onion, thinly sliced
04 - 1 large white onion, thinly sliced
05 - 1 teaspoon Worcestershire sauce
06 - 1 teaspoon spicy mustard
07 - 1 teaspoon Italian seasoning
08 - 0.5 teaspoon garlic powder
09 - 0.5 teaspoon granulated sugar (optional)
10 - 0.5 teaspoon fine sea salt, or to taste
11 - 0.25 teaspoon ground black pepper, or to taste

→ Sandwich Assembly

12 - 8 slices sourdough or French bread
13 - 120 grams Gruyère cheese, sliced or shredded
14 - 120 grams provolone cheese, sliced
15 - 2 tablespoons mayonnaise or softened butter, for spreading (optional)

# Steps to Cook:

01 - Melt butter and olive oil together in a large skillet over medium heat. Add sliced yellow and white onions. Stir to coat evenly and sauté for 2 minutes.
02 - Add Worcestershire sauce, spicy mustard, Italian seasoning, garlic powder, granulated sugar if using, salt, and pepper to the onions. Continue cooking, stirring occasionally, for 25–35 minutes until onions are very soft and deeply golden.
03 - Preheat a clean skillet or griddle over medium heat.
04 - Spread mayonnaise or softened butter on one side of each bread slice. Place half the slices mayo-side down. Top with provolone, a generous layer of caramelized onions, then Gruyère. Close with the remaining bread, mayo-side out.
05 - Place assembled sandwiches in the preheated skillet. Cook for 2–3 minutes per side or until the bread is golden brown and the cheese is fully melted, pressing gently with a spatula for even browning.
06 - Remove sandwiches from the skillet, slice in half, and serve immediately.

# Extra Suggestions:

01 - Caramelizing onions slowly over medium heat develops their natural sweetness; do not rush this step for best flavor.
02 - Mayonnaise creates an especially crisp, golden crust when grilling, but butter is a classic alternative.
03 - Prepare caramelized onions up to 3 days in advance and refrigerate until ready to assemble sandwiches.
04 - For even cheese melting, shred cheese or slice it thinly and cover the pan briefly to trap steam.

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