These Fried Onions for Burgers are cooked in avocado oil and butter on the Blackstone until soft, sweet, and golden. They cost just $0.54 per serving and are ready in under 15 minutes.
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My husband loves burgers, and fried onions are the topping he requests every time we use the Blackstone. They cook right alongside the patties and soak up extra flavor as they sauté. After 14 years of developing recipes, I know simple toppings can make a big difference, and these golden buttery onions always do.
Why You’ll Love Fried Onions for Burgers!
- Budget Friendly — $2.15 total for a topping that makes any burger taste restaurant-quality
- The Blackstone flat top is the ideal surface
- Ready in 15 minutes
- Butter and avocado oil together give you the richest, most satisfying golden sautéed onion without burning
Why Fried Onions Make Every Burger Better
Fried onions are the ultimate topping to your favorite hamburgers recipe. It pairs perfectly with slice tomatoes, mustard, lettuce, cheese, pickles, and ketchup. Choose onions that are cooked soft or golden and crispy. They add flavor and texture to your burger patties so every bite is mouthwatering.
Take your onion burger to the next level by adding this budget friendly topping that is quick to make on the Blackstone or in a pan.
Ingredients
- Yellow onions — two standard yellow onions give you the perfect amount of topping for 4 burgers. Yellow onions have the ideal balance of sharpness when raw that mellows into a sweet depth when sautéed. Sweet Vidalia onions give an even milder result. White onions give a sharper flavor. Red onions work beautifully and give a slightly more colorful presentation
- Avocado oil — high smoke point neutral oil that handles the Blackstone’s medium-high heat without burning. Canola or vegetable oil work equally well. Never use olive oil at this heat level
- Butter — adds the rich buttery depth that oil alone cannot replicate and gives the onions their signature golden color and irresistible flavor. Always add alongside the oil — butter alone burns at medium-high heat
Tools you Need
Having the right tools makes it easy to cook food on your Blackstone Griddle. These are the best tools that we recommend.
- Blackstone
- Blackstone spatula tools
- Thermometer Gun
How to Fry Onions on Blackstone
Step 1 – Cut and Prepare your Onions – Cut the onions in half with a sharp knife. Then cut the ends off of each half and peel the onions. Slice the onions into thin half moons and separate the rings with your fingers.
Step 2 – Prepare your Griddle – Preheat the Griddle or Blackstone Griddle over medium heat (approximately 350-400 degrees F). Place the onions directly on the hot griddle and place the avocado oil and butter on top. Spread onions into an even layer so they brown instead of steam.
Step 3 – Begin Cooking Onions – Sauté the onions for about 10-15 minutes stirring them every few minutes until the the onions are soft and a light brown color. You can also top the onions with a burger press to speed up the caramelization process as well and the onions will brown quicker.
Step 4 – Perfectly Deep Golden Brown Grilled Onions – Then they are ready to serve with your favorite type of ground beef burger and enjoy.
Stovetop Cast Iron Method
No Blackstone? Here is how to make these indoors:
Heat a large cast iron skillet or heavy skillet over medium-high heat. Add the avocado oil and butter and let the butter melt. Add the sliced onions and cook for 10–15 minutes stirring every 2–3 minutes until soft and golden. The result is nearly identical to the Blackstone method — the cast iron holds heat well and gives you the same golden sauté.
Tips for Success
- Spread in a single layer. Piled onions steam — spread thin for a proper sauté and golden color
- Stir every 2–3 minutes. Too frequent stirring prevents browning — too infrequent causes burning. Every 2–3 minutes is the sweet spot
- Add a splash of liquid if needed. If onions begin sticking add a small splash of water beef broth or even beer and stir to release — this deglazes the griddle and adds incredible flavor
- Cook alongside the burgers. Push onions to a cooler zone of the Blackstone while the patties sear in the center — the onions absorb beef drippings and finish at the same time as the burgers
- Do not rush the heat. Medium-high is the right temperature — too high burns the butter before the onions soften and too low gives you steamed rather than sautéed onions
Variations
- Add a pinch of salt and black pepper directly to the onions during cooking for extra seasoning throughout
- Add a teaspoon of Worcestershire sauce in the last 2 minutes for a deeper savory umami note
- Add a pinch of brown sugar in the last minute for a slightly caramelized result without the full 40-minute caramelization commitment
- Swap yellow onions for sweet Vidalia onions for the mildest most sweet result
- Add sliced bell peppers to the griddle alongside the onions for a fajita-style topping
Which Onions are Best for Grilling
- Red Onions – Great for burgers, steak, sandwiches, and salads.
- Yellow Onions – Yellow onions have a milder flavor and are great for burgers, stir-fry’s, fajitas, casseroles, and Mexican dishes.
- Sweet Onions – These sweet onions are perfect on pizza, pasta, and sauces.
Ways to Use Grilled Onions
- Burgers – Try it on Butter Burgers, Blackstone Cheeseburgers, Oklahoma Fried Onion Burger and Crack Burgers
- Casseroles – Adds flavor and texture to many casserole recipes
- Mexican Dishes – Add it to Blackstone Street Tacos and Grilled Stuffed Burritos
- Sandwiches – Prime Rib Sandwich and Cuban Grilled Sandwich are even better topped with these grilled onions.
- Stir-Fry’s – Try these grilled onions with Blackstone Teriyaki Chicken Stir Fry
- Side Dish – You can even serve these as a side dish to Chipotle Steak
Storage Instructions
Refrigerator
- Store in an airtight container for up to 3–4 days — sautéed onions reheat beautifully and are an excellent make-ahead burger topping
Reheating
- Reheat in a skillet over medium heat for 2–3 minutes stirring occasionally — or microwave in 30-second intervals until warmed through
Make Ahead
- Make a full batch on Sunday and refrigerate — burger night all week is significantly faster when the onions are already done
Frequently Asked Questions
At medium-high heat the onions are perfectly soft and golden in 10–15 minutes — stir every 2–3 minutes for the most even result.
The griddle temperature was too low or the onions were piled too thick — always spread in a thin single layer at medium-high heat for proper sautéing rather than steaming.
Yes. Oil prevents sticking and helps with browning.
Yes. Oil alone works, but butter adds flavor.
Cook over medium heat and stir every few minutes.
Yes. Store in fridge up to 5 days and reheat on skillet.
Yes — this is the best approach on the Blackstone. Start the onions first then add the burger patties to the center of the griddle and push the onions to a cooler edge zone to finish slowly while the burgers sear.
Sautéed onions are soft and golden and take 10–15 minutes — caramelized onions are deeply sweet jammy and brown and take 35–45 minutes of low slow cooking. Both are delicious on burgers but give completely different results.
More Easy Grilling Recipes
Learning how to fry onions on the Blackstone is one of those simple skills that makes a big difference. In just a few minutes, you can turn basic sliced onions into a sweet, flavorful topping that takes burgers, sandwiches, and even steak to the next level.
Once you try them this way, you’ll want to add fried onions to everything. If you make them, let us know how you served them — we’re always looking for new ideas to pile on the griddle!
How to Fry Onions for Burgers
Ingredients
- 2 Yellow Onions
- 1 Tbsp Avocado Oil
- 1 Tbsp Butter
See how we calculate recipe costs.
Instructions
- Cut yellow onions in half. Trim off the ends, peel the onions, slice them into thin half moons, and separate the rings with your fingers.
- Preheat the Griddle or Blackstone Griddle over medium high heat (approximately 350-400 degrees F).
- Place the sliced onions directly on the griddle. Add avocado oil and butter on top of the onions.
- Sauté the onions for 10 to 15 minutes, stirring every few minutes, until the onions are soft and light brown.
- Then they are ready to serve with your favorite type of burger and enjoy!
Recipe Video
Recipe Notes
These are best served fresh but you can also refrigerate them for up to 5 days.
You can also top the onions with a burger press to speed up the cooking process as well and the onions will brown quicker.
What can you substitute for the avocado oil?
You can use vegetable oil. I don’t recommend olive oil, because it cannot handle the high heat.