Sourdough Grilled Cheese Onions (Print)

Tangy sourdough with melted Gruyere and sweet caramelized onions create a rich and flavorful sandwich.

# Ingredients:

→ 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 ground black pepper to taste

# Instructions:

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 to 18 minutes until deep golden brown. Add sugar halfway through if desired for enhanced sweetness. Set aside.
02 - Lay out sourdough slices on a clean work surface. Butter one side of each slice evenly.
03 - Place half the Gruyere cheese on the unbuttered side of two slices. Top each with half the caramelized onions, then season with thyme or black pepper if desired. Layer remaining cheese over onions, then place remaining bread slices on top with buttered side facing outward.
04 - Heat a large skillet or griddle over medium-low heat. Place assembled sandwiches in the pan. Cook for 3 to 4 minutes per side, pressing gently with spatula, until bread achieves golden-brown color and cheese fully melts.
05 - Remove sandwiches from pan and allow to rest for 1 minute. Slice diagonally and serve hot.

# Pro Tips:

01 -
  • The sourdough's tanginess plays beautifully against the sweet, jammy onions in a way that feels accidentally sophisticated.
  • Gruyere melts into this creamy, nutty blanket that makes you forget you're eating something simple enough for lunch.
  • Those caramelized onions take time but demand almost nothing from you, just occasional stirring while you do other things.
02 -
  • Don't rush the onions or crank up the heat thinking it will save time, because they'll brown unevenly and lose that sweet, jammy quality that makes this sandwich worth making.
  • Medium-low heat for the sandwich itself is essential, otherwise the outside chars before the cheese has a chance to melt properly inside.
03 -
  • Caramelize your onions the night before and refrigerate them in a container, then everything comes together in 10 minutes on the day you want to eat.
  • Press the sandwich gently while it cooks but don't squash it like you're angry at it, because you want the bread to stay distinct from the filling.
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