Blackstone Patty Melt: Caramelized Onions, Swiss, Crispy Rye
A patty melt is a burger crossed with a grilled cheese — a thin ground beef patty, sweet caramelized onions, melted Swiss, all sandwiched between buttered rye bread and pressed on a flat griddle until both sides are deeply golden and the cheese is fully melted. It’s a diner classic, and the Blackstone makes it better than any diner version because you’re pressing an entire flat surface uniformly instead of hoping a pan stays even.
The most important thing to know: caramelized onions take 25–30 minutes at low heat. You cannot rush them. Start them before anything else and let the griddle do the work.
Prep time: 10 minutes · Cook time: 35 minutes · Serves: 4
Griddle temperature: 375 degrees F (medium heat)
Ingredients
Patty Melts:
- 1.5 lbs 80/20 ground beef
- 8 slices rye bread (marble rye works well)
- 8 slices Swiss cheese
- 3 tbsp butter (for bread and onions)
- Salt and black pepper
Caramelized Onions:
- 2 large yellow onions, thinly sliced
- 2 tbsp butter
- 1 tsp brown sugar (optional, speeds up caramelization)
- Pinch of salt
Optional Sauce:
- 2 tbsp mayonnaise
- 1 tbsp Dijon mustard
- ½ tsp Worcestershire sauce
Instructions
Step 1: Caramelize the Onions
Preheat your Blackstone to medium-low. Add 2 tbsp butter and the sliced onions. Spread them out and cook, stirring every 3–4 minutes, for 25–30 minutes until deeply golden brown and sweet. Add the brown sugar halfway through if you want to speed it up slightly. Salt lightly when done and push to a low-heat zone on the side.
Step 2: Form the Patties
Divide the ground beef into 4 equal portions (about 6 oz each). Press each one into a thin, flat oval roughly the same shape as your bread slices — patty melts are pressed, not thick. Season both sides with salt and black pepper.
Step 3: Cook the Patties
Raise one zone of the Blackstone to medium-high. Cook the patties 3–4 minutes per side until a crust forms and internal temp reaches 160°F. Move to a warm side zone when done.
Step 4: Build and Press
Butter one side of each rye bread slice. On the griddle (medium heat), lay 4 slices butter-side down. Top each with: 1 slice Swiss, 1 patty, a good spoonful of caramelized onions, another slice of Swiss, then the top bread slice butter-side up. Press down firmly with a spatula.
Step 5: Toast and Flip
Cook 2–3 minutes until the bottom is deep golden brown. Carefully flip and press again. Cook another 2–3 minutes until both sides are evenly golden and the cheese is completely melted.
Step 6: Serve
Cut diagonally and serve immediately. The optional sauce (mayo, Dijon, Worcestershire mixed together) is excellent spread on the bread before building the sandwich.
Tips for the Best Patty Melt
- Thin patties only. A patty melt is not a burger — the patty should be thin enough that it fits inside the sandwich without lifting the bread. Press it to roughly ½ inch thick before it goes on the griddle.
- 80/20 beef. The fat keeps the thin patty juicy and gives it flavor. Lean beef on a flat-top dries out fast, especially when the patty is pressed thin.
- Two layers of cheese. One slice on each side of the patty means both layers melt into the bread and the meat. One layer on top doesn’t melt as evenly.
- Press with a spatula. On the Blackstone you can put a second spatula or a burger press on top and lean into it while the bread toasts. You want the bread flat against the griddle for even browning.
- Rye bread is non-negotiable. The earthiness of rye is what separates a patty melt from a grilled cheese with a burger in it. Marble rye or classic seeded rye, both work.
More flat-top recipes: Blackstone Ground Beef Recipes · Blackstone Griddle Sandwiches
Frequently Asked Questions
What is a patty melt?
A patty melt is a diner sandwich made with a thin ground beef patty, caramelized onions, Swiss cheese, and buttered rye bread griddled flat on both sides. It sits between a burger and a grilled cheese — it has the beef and onions of a burger but is cooked like a grilled cheese, pressed flat until the bread is golden and the cheese is melted through.
What’s the difference between a patty melt and a burger?
A patty melt is pressed flat on a griddle like a sandwich and served on rye bread. A burger sits in a bun. The patty for a melt is formed thin and flat (to fit inside the bread), caramelized onions are required (not just toppings), and the whole assembly is griddled on both sides. The result is closer to a grilled sandwich than a burger.
What cheese is best for a patty melt?
Swiss is traditional and the best choice — it melts well and the mild nuttiness complements the sweet caramelized onions. American cheese is a common substitute that melts even more easily. Gruyère is an excellent upgrade if you want richer flavor.
How do you keep a patty melt from being greasy?
Use 80/20 beef (the fat gives flavor but shouldn’t be excessive), butter the bread lightly rather than heavily, and cook on medium heat — not high. High heat burns the bread before the cheese melts, and it can cause butter to pool. Medium heat gives you time to toast the bread evenly while the cheese melts fully.
Can you make patty melts ahead of time?
You can caramelize the onions up to 3 days in advance and refrigerate them — they reheat in 2 minutes on the griddle. The patties can be formed ahead. But the sandwich itself should be assembled and griddled fresh; a reheated patty melt loses the crisp bread texture.
What temperature do you cook patty melts on a Blackstone griddle?
Cook patty melts at 375 degrees F (medium heat) on a Blackstone griddle. Medium heat gives the rye bread time to build a deep golden crust while the burger reaches 160 degrees F and the Swiss melts completely, about 4 minutes per side. Higher heat burns the bread before the cheese melts.