French Onion Grilled Cheese
It’s soup season without the soup. Caramelized onions collapse into jammy gold, glued together with melty Gruyère and a swipe of Dijon between buttery sourdough. The result? A grilled cheese that whispers “bistro chic” but takes less effort than finding your slippers.
Ingredients
- 2 tbsp unsalted butter divided
- 1 tbsp olive oil
- 2 large yellow onions thinly sliced
- 1 tsp sugar optional, for quicker caramelizing
- ½ tsp salt
- 1 tbsp balsamic vinegar or sherry vinegar
- 8 slices sourdough bread
- 2 tsp Dijon mustard
- 2 cups shredded Gruyère cheese or Swiss/Emmental mix
- 4 slices provolone optional, for extra melt factor
- Fresh thyme leaves optional garnish
Instructions
- Heat 1 tbsp butter + olive oil in a skillet. Add onions, sugar, and salt. Cook low and slow (15–20 minutes) until golden and jammy. Deglaze with balsamic; stir until glossy.
- Spread Dijon mustard thinly on one side of 4 bread slices.
- Layer Gruyère, a pile of onions, and optional provolone. Top with remaining bread.
- Heat remaining butter in skillet. Grill sandwiches 3–4 minutes per side, pressing gently, until bread is crisp and cheese oozes.
- Sprinkle with fresh thyme before serving if you’re feeling smug.
Notes
• Shortcuts: Use pre-sliced onions or caramelized onion jam from a jar if you’re truly fried.
• Cheese swap: Cheddar + mozzarella also bring the melty drama.
• Toddler hack: Skip the mustard and cut into dippable sticks.
• Apéro energy: Slice into thirds and serve with cornichons + a glass of whatever’s open.
• Cheese swap: Cheddar + mozzarella also bring the melty drama.
• Toddler hack: Skip the mustard and cut into dippable sticks.
• Apéro energy: Slice into thirds and serve with cornichons + a glass of whatever’s open.