Sourdough grilled cheese onions (Printable)

Tangy sourdough paired with melty Gruyere and sweet caramelized onions in a flavorful sandwich.

# What You Need:

→ Bread & Cheese

01 - 4 slices sourdough bread
02 - 5 oz Gruyere cheese, grated or thinly sliced

→ Onions

03 - 1 large yellow onion, thinly sliced
04 - 1 tablespoon unsalted butter
05 - 1 teaspoon olive oil
06 - 1/4 teaspoon salt
07 - 1/2 teaspoon sugar

→ For Grilling

08 - 2 tablespoons unsalted butter, softened

→ Optional Additions

09 - Fresh thyme leaves or black pepper to taste

# How-To Steps:

01 - Heat 1 tablespoon butter and olive oil in a skillet over medium heat. Add sliced onions and salt. Cook, stirring occasionally, for 15-18 minutes until golden brown and deeply caramelized. Add sugar halfway through if extra sweetness is desired. Set aside.
02 - Lay out sourdough slices and butter one side of each slice.
03 - Place half the cheese on the unbuttered side of two bread slices. Top each with half the caramelized onions, then sprinkle with thyme or black pepper if using. Cover with remaining cheese and top with other bread slices, buttered side facing outward.
04 - Heat a large skillet or griddle over medium-low heat. Place sandwiches in the pan and cook for 3-4 minutes per side, pressing gently, until bread is golden brown and cheese is fully melted.
05 - Remove from pan and let rest for 1 minute. Slice diagonally and serve hot.

# Expert Suggestions:

01 -
  • The caramelized onions turn ordinary grilled cheese into something genuinely special without requiring fancy techniques.
  • Sourdough's natural tang cuts through the richness of cheese so every bite feels balanced and exciting.
  • It comes together in under 45 minutes but tastes like you've been cooking all afternoon.
02 -
  • Don't skip the resting time between cooking and serving—it's the difference between a sandwich that holds together and one that turns into a molten mess on your plate.
  • Medium-low heat is non-negotiable because even a few minutes too hot and your bread burns dark while the cheese stays cold in the center.
03 -
  • If your sourdough is particularly thick, slice it horizontally so you get thinner pieces that cook through evenly without the crust getting too dark.
  • Press the sandwich gently as it cooks—just enough to encourage contact with the pan, not so hard that you squeeze out all the cheese.
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