Caramelized Onion Patty Melt

Name: Caramelized Onion Patty Melt with Special Sauce
Prep time: 15 min
Cook time: 1 h 25 min
Total time: 1 h 40 min
Yield: 1 servings
Cuisine: American
Ingredients: 2 large onions, diced; 3 tbsp unsalted butter; 1 tbsp vegetable oil; 1/2 tsp salt, plus more to taste; 1/2 cup mayonnaise; 2 tbsp ketchup; 2 tbsp sweet pickle relish; 1/2 lb 80/20 ground beef; 1/2 tsp dried rosemary; black pepper, to taste; 2 slices thick-cut white bread; 2 slices Swiss cheese; 1 slice American cheese

A patty melt featuring deeply caramelized onions, a juicy smashed burger patty, and tangy special sauce grilled between thick slices of bread—delivering rich, savory flavor in every bite.

🌍American 🏷️Patty melt 🏷️Sandwich 🏷️Burger 🏷️Caramelized onions American cheese

🏷️

🏷️Comfort food

-0:00

thatdudecancookonTikTok

Total

1h 40m

Servings

1

Difficulty

Medium

Est. Cost

$25–$41

Recipe Source

View original recipe

From TikTok · by thatdudecancook

-0:00

thatdudecancookonTikTok

Ingredients

2 large onions, diced
3 tbsp unsalted butter
1 tbsp vegetable oil
1/2 tsp salt, plus more to taste
1/2 cup mayonnaise
2 tbsp ketchup
2 tbsp sweet pickle relish
1/2 lb 80/20 ground beef
1/2 tsp dried rosemary
black pepper, to taste
2 slices thick-cut white bread
2 slices Swiss cheese
1 slice American cheese

13 Ingredients

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Instructions

1
To make the caramelized onions, dice the onions finely. In a large pot or Dutch oven over low heat, melt the butter and oil.
2
Add the diced onions and salt to the pot. Cook over low heat, stirring occasionally, for about 1 hour and 20 minutes, or until the onions are deeply browned, sweet, and jammy.
3
While the onions cook, prepare the sauce. In a small bowl, combine the mayonnaise, ketchup, and pickle relish. Mix until smooth and set aside.
4
Form the ground beef into a ball. Place it between two sheets of parchment paper and press into a thin, wide patty that is slightly larger than your bread slices.
5
Season both sides of the beef patty generously with salt, black pepper, and dried rosemary.
6
Heat a skillet over high heat. Cook the patty for 2-3 minutes per side until a deep brown crust forms. Remove from the skillet and set aside.
7
In the same skillet, using the rendered beef fat, toast the bread slices until golden brown on one side.
8
Flip the bread slices. Spread sauce on the toasted side of one slice. Place the cooked patty on top, followed by the slice of American cheese.
9
Top the patty with a generous amount of the caramelized onions, then drizzle with more sauce.
10
Place the second slice of bread on top to complete the patty melt. Press down gently, slice in half, and serve immediately.

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Tips & Notes

Pro tips

Don't rush caramelization—low, steady heat over 30-40 minutes builds complex sweetness; high heat creates brown onions, not caramelized ones.
Smash the burger patty hard with a spatula immediately after placing it on the hot surface to maximize crust and browning.
Butter the outside of the bread before grilling, not the inside, to ensure even browning and prevent the filling from soaking through.
Toast the assembled sandwich on a griddle or skillet over medium heat, pressing gently, until the bread is golden and the cheese (if added) melts.

Substitutions

80/20 ground beef → 85/15 ground beef (slightly leaner, will be drier; compensate by not overcooking)
Sweet pickle relish → dill pickle relish (more tangy, less sweet)
Dried rosemary → fresh thyme (milder flavor; use 1 tsp fresh)
Unsalted butter → salted butter (reduce added salt by 1/4 tsp)

Storage & make-ahead

Store leftover caramelized onions and special sauce separately in airtight containers for up to 4 days; reheat onions gently on the stovetop and assemble fresh patty melts to order.

Common Questions

How long does it take to caramelize the onions?

Caramelizing onions typically takes 30-40 minutes over medium heat, stirring occasionally. This low-and-slow approach develops deep sweetness and color.