Sourdough Grilled Cheese Onions (Printable)

Tangy sourdough layered with melted Gruyere and sweet caramelized onions creates a rich, 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 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 if desired for enhanced sweetness. Set aside.
02 - Lay out all sourdough slices. Butter one side of each slice with softened butter.
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. Add remaining cheese and top with other bread slices, buttered side facing outward.
04 - Heat a large skillet or griddle over medium-low heat. Place assembled sandwiches in the pan. Cook for 3-4 minutes per side, pressing gently, until bread is golden and cheese is completely melted.
05 - Remove sandwiches from pan and let rest for 1 minute. Slice diagonally and serve immediately while hot.

# Expert Suggestions:

01 -
  • The sharpness of the Gruyere melts perfectly into the sweet, soft onions.
  • Sourdough provides a robust, tangy crust that stands up to the rich filling.
  • Simple pantry staples are transformed into a gourmet café-style meal.
02 -
  • For a more even melt, grate the Gruyere instead of using slices.
  • If your onions start to stick or brown too fast, add a teaspoon of water to the pan to deglaze them.
  • Don't skip the rest time; letting the sandwich sit for 60 seconds helps the cheese set so it doesn't all slide out when you cut it.
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