There’s something about the sweetness of richly caramelized onions that makes any meal extra delicious & fancy-feeling. A caramelized onion burger is the perfect example – the simple addition of caramelized Vidalia onions takes a humble summer burger to gourmet heights, & it couldn’t be easier!
You’ll start by caramelizing the onions. This “low & slow” process cannot be rushed, but using an extra-sweet variety, like Vidalia onions, & slicing them really thinly helps speed things along. Be sure to check out the blog post, above, for lots more tips, tricks, & even make-ahead guidance.
To make the caramelized onion burger patties, simply mix the onions into ground beef with a few other flavor-boosting ingredients & dinner’s well on its way! We love cooking these burgers on the grill, but feel free to use a flat top or a cast iron skillet on your stovetop – whatever works best for you.
As far as serving goes, we always pop ’em on a buttery-soft brioche burger bun & serve with classic burger fixings. For an extra special touch, whip up a little tangy-creamy Dijonnaise (details in the Recipe Notes, below!), which balances the savory-sweetness of these burgers beautifully. ♡ Enjoy!
for the caramelized onion burgers:
- 1 pound 85% lean ground beef
- caramelized onions, below
- 1 tablespoon Worcestershire sauce
- 2 teaspoons Dijon mustard
- 1 teaspoon garlic powder
- kosher salt & ground black pepper, to season
- for serving, as desired: toasted brioche buns, cheese of choice, lettuce, tomato, mustard, ketchup, Dijonnaise (see Recipe Notes), etc.
for the caramelized onions:
- 2 pounds Vidalia onions, thinly sliced
- 4 tablespoons unsalted butter
- kosher salt, to season
- ½ cup dry sherry (see Recipe Notes, below)
- Soften the Vidalia onions: Add the butter to a large, heavy-bottomed pot with a lid over medium heat (I use a 5-qt Dutch oven). Once melted, add the sliced Vidalia onions, stirring to coat. Cover the pot. Cook 12-15 minutes, until softened & fragrant. The onions shouldn’t require too much attention at this point, but feel free to uncover & stir occasionally.
- Caramelize the Vidalia onions: Once softened, uncover the pot & reduce heat to medium-low. Season the onions with 2 teaspoons kosher salt, stirring to combine. Continue to cook, stirring occasionally, until tender, fragrant, & deeply browned, 30-45 minutes more. Helpful hints: Be sure to adjust heat as needed to allow the onions to caramelize slowly & prevent burning. The closer the onions get to reaching caramelization, the more often you will want to stir to promote even browning & prevent burning.
- Deglaze: Once the onions are caramelized, deglaze the skillet. Slowly pour in the dry sherry, using a wooden spoon to scrape up any browned bits formed on the bottom of the pan. Increase the heat to medium-high to bring the wine to a simmer, then simmer 2-3 minutes or until reduced. Remove from the heat & set aside in a small bowl to cool slightly for caramelized onion burger assembly or store in an airtight container in the refrigerator for up to 1 week.
- Mix & form the caramelized onion burger patties: To a large mixing bowl, add the ground beef, caramelized Vidalia onions, Worcestershire sauce, Dijon mustard, & garlic powder. Season with 1 teaspoon kosher salt & ground black pepper as desired. Use your hands to mix until just combined – overworking the blue cheese burger mixture will lead to tough burgers, so take care not to overmix. Divide the burger mixture into 4 even portions. Form each portion into a burger patty slightly larger than the size of your buns, pressing a small indent in the center of each patty to prevent the burgers from swelling on the grill. Place the caramelized onion burger patties on a plate or a small baking sheet & set aside for grilling.
- Grill the caramelized onion burgers. Preheat the grill to medium heat, about 450-500 degrees F. Just before placing the burgers on the grill, generously oil a wad of paper towels. Use grilling tongs to run the oiled paper towels over the grill grates, generously oiling the grates. Place the burgers directly on the grill grates. Grill 3-5 minutes per side, keeping the grill lid closed as the burgers cook. If you’d like to top your caramelized onion burgers with cheese, do so when there are 2 minutes left of grilling time. Once cooked to desired doneness (3 minutes per side yields medium doneness on our grill), transfer the burgers to a small baking sheet or plate & let rest for a couple minutes before serving.
- Serve caramelized onion burgers as desired, on toasted buns with lettuce, tomatoes, onions, & whatever burger toppers you love most. Enjoy!
- Ingredient Notes:
- Vidalia onions are a super special sweet onion variety harvested exclusively in 20 counties in South Georgia. While all onions have some natural sweetness, a Vidalia onion’s abundance of sugars makes them a fantastic choice for caramelizing. Look for Vidalia onions in the produce section at your grocery store during spring & summer months (from about April to early September).
- Sherry is a Spanish fortified wine, meaning it is a wine that is “fortified” with a distilled spirit, most often fortified with brandy. While sherry ranges in style, you will want to use dry sherry (often labeled “Fine” or “fino“) for this recipe. Dry sherry is often used in French onion soup (just take a look at Julia Childs’ & Ina Garten’s iconic recipes!), as its nutty flavor complements the nuttiness of gruyère cheese & its crispness helps cut through the rich flavor of the caramelly onions. You should be able to find dry sherry easily in the fortified wine section at your favorite wine or liquor shop. Sherry substitutes. ⇢ If you cannot find dry sherry, you can substitute with dry vermouth or dry, unoaked white wine for this recipe. If you prefer not to cook with alcohol, substitute with an equal amount of beef stock with a splash of apple cider vinegar whisked into it.
- Dijonnaise: My favorite burger sauce for caramelized onion burgers is dijonnaise, which is essentially a Dijon mustard aioli. To make, simply combine ⅓ cup mayonnaise, 2 tablespoons Dijon mustard, 1 clove garlic. Season to taste & mix to combine well. Set aside for burger assembly, or store in an airtight container in the refrigerator for up to 5 days.
- Alternate Cooking Method: Stovetop Caramelized Onion Burgers: If you do not have access to an outdoor grill, you can also cook these caramelized onion burgers on the stovetop using a grill pan or a well-seasoned cast-iron skillet. Add 1-2 tablespoons of olive oil to the skillet over medium-high heat. Once hot, add the caramelized onion burgers, working in batches as needed to avoid overcrowding the pan, & cook according to Step 5 of Recipe Directions, above.
- Meal Prep: While there’s a few components involved in this caramelized onion burger recipe, you can easily cut down on active prep time at dinnertime by prepping one or two in advance:
- Caramelize the onions according to Steps 1-3 of Recipe Directions, above. Store in an airtight container in the refrigerator for up to 1 week. (20 minutes active prep)
- Prep & form the caramelized onion burger patties according to Step 4 of Recipe Directions, above. Transfer the formed patties to an airtight container, separating them with a piece of wax or parchment paper. Refrigerate for up to 3 days. When you’d like to make dinner, simply preheat the grill & get cooking – easy! (10 minutes active prep)