Crispy Onion Grilled Cheese (Printable)

Golden fried onions layered with melted cheddar and mozzarella between toasted bread for an irresistible crispy, gooey sandwich.

# Ingredient List:

→ Crispy Fried Onions

01 - 1 small yellow onion, thinly sliced into rings
02 - 1/2 cup all-purpose flour
03 - 1/4 cup cornstarch
04 - 1/2 teaspoon salt
05 - 1/2 teaspoon black pepper
06 - 1/2 teaspoon paprika
07 - 1/2 cup buttermilk, or whole milk with 1 teaspoon lemon juice
08 - Vegetable oil for frying (approximately 2 cups)

→ Sandwich Assembly

09 - 4 slices sourdough bread or thick-cut white bread
10 - 4 tablespoons unsalted butter, softened to room temperature
11 - 1 cup sharp cheddar cheese, freshly grated (approximately 4 ounces)
12 - 1 cup whole milk mozzarella cheese, freshly grated (approximately 4 ounces)

# Directions:

01 - Set up two shallow bowls. In the first bowl, whisk together flour, cornstarch, salt, black pepper, and paprika until thoroughly combined. Pour buttermilk into the second bowl. This assembly-line setup ensures efficient dipping and coating.
02 - Working with a handful of onion slices at a time, submerge them in buttermilk for 10 seconds. Transfer to the flour mixture, pressing gently to adhere coating. Shake off excess flour and place coated slices on a plate. Repeat until all onions are coated.
03 - Pour vegetable oil into a large skillet to a depth of 1 inch. Heat over medium-high until oil reaches 350°F (175°C)—a small drop of batter should sizzle immediately. Fry coated onions in batches without overcrowding, flipping once, until golden brown and crispy, about 2–3 minutes total. Transfer to paper towels to drain.
04 - Butter one side of each bread slice generously. Place two slices butter-side down on your work surface. These will form the base of your sandwiches.
05 - Distribute half the cheddar evenly over the two butter-side-down slices. Top with half the mozzarella. Arrange a generous layer of crispy fried onions over the cheese, then cover with remaining cheddar and mozzarella. The double layer of cheese helps bind the onions between the bread.
06 - Place the remaining bread slices on top, butter-side facing outward. Press down gently to compact the layers.
07 - Heat a clean nonstick skillet or griddle over medium-low heat. Transfer sandwiches carefully to the pan. Cook for 3–4 minutes until the bottom bread is golden brown and cheese begins to melt. Flip and cook the second side for an additional 3–4 minutes until deeply golden and cheese is fully melted throughout.
08 - Remove sandwiches from pan and let rest on a cutting board for 1–2 minutes. This brief resting period allows the cheese to set slightly, making for cleaner slices. Cut each sandwich diagonally in half and serve immediately while hot and crispy.

# Expert Tips:

01 -
  • The contrast between the shattering crisp of the onions and the molten cheese creates a texture experience that regular grilled cheese cant match.
  • Its secretly impressive enough for guests but doesnt require any fancy ingredients you wouldnt already have in your pantry.
02 -
  • The oil temperature is everything – too hot and onions burn before crisping, too cool and they absorb oil and become greasy.
  • Slicing bread slightly thicker than normal (about 1/2 inch) creates the ideal ratio of crispy exterior to gooey interior.
03 -
  • After flipping the sandwich, add a small cover over the pan for 30 seconds to trap heat and ensure the cheese melts perfectly without burning the bread.
  • Grating the cheese rather than using slices creates more surface area that melts faster and more evenly, preventing that half-melted cheese disappointment.
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