This is not your average grilled cheese. Fontina melts into something almost impossibly creamy, and caramelized onions add a sweetness that makes this feel less like a weeknight quick fix and more like something worth sitting down for.

Ingredients

  • 2 thick slices sourdough bread
  • 4 ounces fontina cheese, thinly sliced
  • 1 medium yellow onion, thinly sliced
  • 2 tablespoons butter, softened
  • 1 teaspoon fresh thyme leaves
  • Salt and black pepper to taste
  • 1 tablespoon olive oil

Step-by-Step Instructions

Step 1: Caramelize the Onions

In a medium skillet, heat olive oil over medium-low heat. Add the sliced onion with a pinch of salt and cook, stirring occasionally, for 15 to 20 minutes until deep golden and caramelized. Stir in thyme leaves and set aside.

Step 2: Butter the Bread

Spread butter generously on one side of each bread slice. This is not the place to be skimpy.

Step 3: Build the Sandwich

Heat a large skillet or griddle over medium-low heat. Place one bread slice butter-side down and layer half the fontina on top. Add the caramelized onions in an even layer, then top with remaining fontina and the second bread slice, butter-side up.

Step 4: Cook Low and Slow

Cook for 4 to 5 minutes per side until the bread is golden brown and the cheese is fully melted. Press gently with a spatula. Low heat is key here. Rush it and the bread will burn before the cheese melts.

Step 5: Serve Hot

Cut in half and serve immediately. The window between “perfect” and “lukewarm and sad” is about 90 seconds.

Serving Suggestions

  • Serve with a simple arugula salad dressed with lemon and olive oil
  • Add a bowl of tomato soup for the classic combo
  • Pair with a crisp hard cider or a glass of medium-bodied red wine

Tips

  • Use a cast iron skillet if you have one. It holds heat evenly and gives the bread an extra-crispy crust
  • Fontina can vary in quality. Look for an Italian fontina if possible, not the American pre-shredded kind
  • The caramelized onions can be made ahead and stored in the fridge for up to 4 days