These Blackstone smash burgers with onions are the ultimate meal to make on your outdoor griddle. For this classic burger, a juicy seasoned beef patty is cooked together with thinly sliced onion and topped with melted provolone cheese. It's cheeseburger perfection that's ready in less than 30 minutes.

I kept this Blackstone smash burger recipe pretty simple for a reason. Skipping any fillers and seasoning the beef with only salt and pepper lets the flavor of the beef and the fried onions truly shine. The secret to getting a juicy burger patty and perfectly cooked onions is to slice or shave your onions as thin as possible.
[feast_advanced_jump_to]Why You'll Love This Recipe
- You'll love the combination of tender beef, melted cheese, and crispy fried onion in your burger.
- You can scale the recipe to make as many burgers as you need.
- It's ready in less than 30 minutes.
Ingredients and Substitutions
- Ground beef--I recommend using lean ground beef (85/15), which will give you a little bit of fat for flavor. Don't use extra-lean as it may result in a dry burger.
- Onion--Yellow or white onions work well here. I tend to avoid using red onions or sweet onions for these smash burgers, as I find them too sweet.
- Provolone--I think the flavor of provolone complements the beef and onions nicely, but any good melting cheese will work well here, including cheddar, Swiss, or Monterey jack.
How to Make Smash Burgers on the Blackstone
1. Toss the sliced onions with ยผ teaspoon salt and arrange on a double layer of paper towel to drain for 15 minutes.
2. Shape the beef into two patties and sprinkle generously with salt and pepper.
3. Place the beef patties on the griddle and smash to create thin burgers. Let them cook undisturbed until a crust begins to form.
4. While the burgers are cooking, divide the onions between the burgers, piling them evenly on top.
5. Flip the burgers and cook for 2 minutes.
6. Top each burger with cheese and cook until the cheese is melted. Toast the buns while the cheese is melting.
FAQs
The key to perfect onion smash burgers is slicing the onions as thinly as possible. You can do this with a very sharp knife, but for the best results, I recommend using a mandoline.
Yes. Follow the recipe, cooking the burgers over medium high heat. If you're scaling the recipe to make more, I recommend only cooking two or three burgers at a time in your skillet. Overcrowding makes it difficult to flip them and your burgers won't crisp nicely.
Tips and Troubleshooting
- Some areas of your griddle will be hotter than others. Usually the area directly above the flame is the hottest. Cook the burgers on the hottest part of the griddle and use the cooler zone for toasting the buns.
- You can salt and drain the onions and shape the burger patties a few hours in advance and store them in the fridge until you're ready to cook. Don't season the burgers until just before cooking though, as salt will draw moisture from the beef and can result in dry burgers.
More Blackstone Recipes You'll Love
Recipe
Blackstone Smash Burgers with Onions
Ingredients
- ยฝ cup very thinly sliced onion (from about ยฝ medium onion)
- ยผ teaspoon kosher salt plus more for the burger
- 9 ounces (255 g) lean ground beef (85/15)
- Freshly ground black pepper
- 2 slices provolone cheese
- 2 burger buns
- Sliced tomato and shredded iceberg lettuce for serving (optional)
Instructions
- Toss the onions with ยผ teaspoon kosher salt and arrange in a thin layer on a double layer of paper towel. Let the onions drain for 15 minutes. Gently pat dry.
- While the onions are resting, divide the ground beef into two equal portions and shape them into patties about 1-inch thick. Season generously with salt and pepper.
- Preheat the Blackstone or other outdoor griddle to medium.
- Working quickly, place each burger patty on the hot part of the griddle and immediately smash it with a burger press until about โ -inch thick (1 cm). Cook until the underside of the burger begins to brown and develop a crust, 2 to 3 minutes.
- Divide the onions equally between the burgers and pile them in an even layer on the raw side of the burger.
- Flip the burgers so that the onions are now in direct contact with the griddle. Cook until the onions are softened and beginning to crisp, 1 to 2 minutes.
- Top each burger with a slice of cheese and continue to cook until the cheese is melted, 1 to 2 minutes more. While the cheese is melting, place the burger bun halves cut side down on the cooler zones of the griddle to let them toast for 30 seconds.
- Serve the burgers immediately, topped with sliced tomato and shredded lettuce, if desired, along with any other classic burger condiments.
Notes
- Know your zones--Some areas of your griddle will be hotter than others. Usually the area directly above the flame is the hottest. Cook the burgers on the hottest part of the griddle and use the cooler zone for toasting the buns.
- Get ahead--You can salt and drain the onions and shape the burger patties a few hours in advance and store them in the fridge until you're ready to cook. Don't season the burgers until just before cooking though, as salt will draw moisture from the beef and can result in dry burgers.