Caramelized Onion Grilled Cheese (Printable)

Golden-brown sourdough sandwich with jammy caramelized onions and melted sharp white cheddar for ultimate comfort.

# What You’ll Need:

→ Bread & Dairy

01 - 4 slices sourdough or country bread
02 - 2 tablespoons unsalted butter, softened
03 - 4 ounces sharp white cheddar cheese, grated

→ Onions

04 - 2 large yellow onions, thinly sliced
05 - 1 tablespoon olive oil
06 - 1/2 teaspoon salt
07 - 1/2 teaspoon sugar, optional for enhanced caramelization

→ Seasonings

08 - Freshly ground black pepper to taste

# Directions:

01 - Heat olive oil in a large skillet over medium heat. Add sliced onions and salt, stirring to coat evenly. Cook, stirring occasionally, for 20-25 minutes until deeply golden and caramelized. Add sugar halfway through if desired to enhance sweetness and browning.
02 - Remove onions from heat and set aside. Wipe out skillet if needed to remove excess oil.
03 - Butter one side of each bread slice. Place two slices, buttered side down, on a clean surface. Top each with half the grated cheddar, then layer caramelized onions evenly over the cheese. Sprinkle with black pepper. Cover with remaining bread slices, buttered side up.
04 - Heat skillet over medium-low heat. Place sandwiches in skillet and cook 3-4 minutes per side, pressing gently, until bread is crisp and golden and cheese is melted. Adjust heat as needed to prevent burning.
05 - Remove from pan and let rest 2 minutes. Slice diagonally and serve hot.

# Expert Advice:

01 -
  • The onions cook down into something sweet and jammy that tastes like you spent all day on it, even though you didn't.
  • Sharp cheddar cuts through the sweetness perfectly, so every bite feels balanced instead of cloying.
  • It's fancy enough to impress yourself on a quiet night in, but simple enough to make when you're tired.
  • Sourdough crisps up beautifully and holds everything together without getting soggy.
02 -
  • Don't rush the onions, if you crank the heat to save time they'll brown on the outside and stay crunchy inside instead of turning sweet and jammy.
  • Butter the bread all the way to the edges or you'll end up with pale corners that taste like cardboard.
  • Keep the heat medium-low when grilling or the bread will burn before the cheese melts, and nobody wants that kind of heartbreak.
03 -
  • Make a big batch of caramelized onions and keep them in the fridge for up to a week, they're good on everything from eggs to pizza.
  • Press down gently with your spatula while the sandwich cooks, but don't smash it flat or all the cheese will ooze out the sides.
  • Let the sandwich rest for a couple minutes after it comes off the heat, the cheese will firm up just enough to make slicing cleaner and less messy.
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