Sourdough Grilled Cheese Onions (Printer View)

Tangy sourdough, melted Gruyere, and sweet caramelized onions come together in this melty sandwich.

# What you'll 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

# Method:

01 - Heat 1 tablespoon butter and 1 teaspoon 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 for enhanced sweetness if desired. Set aside.
02 - Lay out sourdough slices. Butter one side of each slice generously.
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 place other bread slices on top with buttered side facing outward.
04 - Heat a large skillet or griddle over medium-low heat. Place sandwiches in the pan. 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 immediately while hot.

# Expert Advice:

01 -
  • The caramelized onions add a deep sweetness that makes you forget you're eating something so simple.
  • Gruyere melts like a dream and tastes buttery in a way that elevates the entire sandwich.
  • Sourdough's tang plays perfectly against the richness, keeping everything from feeling too heavy.
02 -
  • Patience with the onions is non-negotiable because rush them and they just soften into sad strings instead of caramelizing into sweet gold.
  • Medium-low heat on the pan is the secret because high heat burns the outside before the cheese inside has time to actually melt.
03 -
  • Grate your Gruyere ahead of time so it's ready to go, and if you're using a block, chill it first because cold cheese shreds cleanly instead of turning into a messy paste.
  • Cook the onions the night before if you're making these for guests, because caramelized onions actually taste better the next day after they've had time to think about their choices.
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