There’s something about a summer evening, the pool glowing in the background, and a griddle heating up on the patio that just says “let’s smash some burgers.” Last night I fired up the Blackstone for a batch of onion smash burgers, and honestly, this might be one of the simplest, most satisfying cooks I’ve done all season. No fancy equipment, no long ingredient list — just beef, onions, butter, and a hot flat top.

If you’ve spent any time over on backyardsmoking.com, you know I lean toward low-and-slow most days. But sometimes you want dinner on the table in twenty minutes, and that’s exactly what smash burgers deliver. Here’s how the whole cook came together, onion crust and all.

What You’ll Need

• 1 lb ground beef, 80/20 blend, divided into 5 equal balls
• 1 onion, sliced paper-thin (a mandoline makes this easy)
• 3 burger buns
• Butter, for the griddle under the burgers
• Butter, for toasting the buns
• Salt, pepper, and garlic powder
• Sliced cheese of your choice — I used a home-smoked white cheddar

Setting Up the Station

Before anything hits the griddle, I like to get everything staged and within arm’s reach. That means the beef portioned into balls, the onions sliced thin, the seasonings lined up, and the cheese sliced and ready to go. Smash burgers move fast once you start, so there’s no time to be running back inside for something you forgot.

For this cook I portioned 1 lb of 80/20 ground beef into 5 loose balls — no need to overwork the meat, just gently form it so it holds together enough to transfer to the griddle. Could have easily portioned into 6, but my daughter typically only does a single instead of a double.

Searing the Beef

With the Blackstone ripping hot, I dropped a little butter under each ball of beef before it went down. That extra fat under the patty helps build a deep, crispy crust and adds a lot of flavor you just don’t get from a dry sear.

The Onion Smash

This is where the “onion burger” style comes in. Instead of smashing the beef flat first, I piled a small handful of thin-sliced onions right on top of each ball, then smashed down through the onions into the meat. The onions get pressed directly into the patty and caramelize right there on the griddle surface, so every bite has that sweet, slightly charred onion flavor baked into the crust.

Right after the smash, I hit each patty with a little salt, pepper, and garlic powder while it’s still sizzling — the heat helps the seasoning stick and start working immediately.

Let the Crust Do Its Thing

Resist the urge to move these around. Once they’re smashed and seasoned, let the onions and beef sit and cook together. You’ll see the onions start to darken and curl at the edges, and the underside of the patty forms that classic lacy, crispy smash-burger crust.

Give it a few more minutes and the onions go from translucent to deeply golden and a little crisp — this is exactly what you want before the flip.

The Flip and the Cheese

Once that crust is set, flip each patty so the onions end up on the bottom, crust-side up. This is the moment of truth on any smash burger — you want to see that deep brown, almost lacy sear. Right after the flip, I laid slices of home-smoked white cheddar over each patty so it had time to fully melt into the burger before coming off the griddle.

Smoking cheese is one of my favorite cooler-weather projects over on backyardsmoking.com — I usually put up 100+ lbs a year and end up gifting most of it, so there’s almost always a block of something smoked in the fridge ready to go on a burger like this one.

Toasting the Buns

While the cheese melted, I buttered the burger buns and set them cut-side down right alongside the patties. A minute or two on the griddle is all it takes to get a golden, slightly crisp surface that holds up to all that juicy beef and onion without turning soggy.

Ready to Build

A few minutes later, everything came together — toasted buns on one side, five onion-crusted, cheese-covered smash burgers on the other. Simple ingredients, minimal cleanup, and a ridiculous amount of flavor packed into each patty.

Final Thoughts

Onion smash burgers are one of those recipes that prove you don’t need a long cook time to get a ton of flavor out of the Blackstone. The onions pressed right into the patty do most of the heavy lifting, and a good smoked cheese on top takes it over the top. If you’ve got 20 minutes and a griddle, this one’s hard to beat for a weeknight dinner or a casual backyard hang by the pool.

Give it a try and let me know how your onions crust up — and if you’re curious about smoking your own cheese for burgers like this, check out the cheese smoking archives on backyardsmoking.com for the full rundown on how I do it.