Quick Recipe Version (TL;DR)
Quick Ingredients
- 2 large yellow onions, thinly sliced
- 1 tbsp unsalted butter + 1 tbsp olive oil
- 1 1/2 lb (680 g) 80/20 ground beef
- 4 oz (115 g) blue cheese, crumbled
- 1 1/2 tsp kosher salt, 3/4 tsp black pepper
- 1 tsp garlic powder, 1 tbsp Worcestershire sauce
- 4 burger buns (brioche or potato)
- Lettuce leaves, tomato slices, mayo, Dijon mustard (optional)
Do This
- 1. Slowly cook onions in butter and oil over medium-low heat until deep golden, 20–25 minutes.
- 2. Preheat grill to medium-high (about 400–450°F / 200–230°C).
- 3. Season ground beef with salt, pepper, garlic powder, and Worcestershire; gently mix.
- 4. Divide beef into 8 equal balls; flatten, add blue cheese to 4 patties, top with remaining 4 and seal edges well.
- 5. Chill patties 10–15 minutes, then grill 5–6 minutes per side, to an internal temp of 160°F (71°C).
- 6. Toast buns on the grill; spread with mayo and/or Dijon.
- 7. Assemble: bun, lettuce, burger, caramelized onions, tomato slices, then top bun. Serve hot.
Why You’ll Love This Recipe
- Juicy, perfectly seasoned burgers with a molten blue cheese center that oozes with every bite.
- Deeply caramelized onions add sweetness that balances the tangy, salty blue cheese.
- Great for grilling season, but easy to adapt for stovetop cooking year-round.
- Feels restaurant-worthy, yet uses simple ingredients and straightforward techniques for home cooks.
Grocery List
- Produce: Yellow onions, lettuce (leaf or romaine), tomato, optional fresh herbs (parsley or chives) for garnish.
- Dairy: Blue cheese, unsalted butter, optional slice cheese (if you want extra melty topping).
- Pantry: Olive oil, kosher salt, black pepper, garlic powder, brown sugar, balsamic vinegar, Worcestershire sauce, mayonnaise, Dijon mustard, burger buns.
Full Ingredients
For the Caramelized Onions
- 2 large yellow onions (about 1 lb / 450 g), thinly sliced
- 1 tbsp unsalted butter
- 1 tbsp olive oil
- 1/2 tsp kosher salt
- 1 tsp light brown sugar (optional, for extra sweetness)
- 1 tsp balsamic vinegar (optional, for a touch of tang)
For the Blue Cheese Stuffed Burgers
- 1 1/2 lb (680 g) ground beef, 80/20 (80% lean, 20% fat)
- 4 oz (115 g) blue cheese, crumbled (such as Gorgonzola, Roquefort, or Stilton)
- 1 1/2 tsp kosher salt
- 3/4 tsp freshly ground black pepper
- 1 tsp garlic powder
- 1/2 tsp onion powder (optional)
- 1 tbsp Worcestershire sauce
- 1 tbsp cold water or milk (optional, for extra juiciness)
For Serving
- 4 burger buns (brioche, potato, or sesame), split
- 4 leaves green leaf lettuce or romaine
- 1 large ripe tomato, sliced into 4 thick slices
- 4 tsp mayonnaise (about 1 tsp per bun, or to taste)
- 2 tsp Dijon mustard (about 1/2 tsp per bun, or to taste)
- Optional: sliced pickles, extra crumbled blue cheese, or fresh chopped parsley/chives for garnish
Step-by-Step Instructions
Step 1: Slowly Caramelize the Onions
Peel and thinly slice the onions from root to tip. In a large skillet, heat the butter and olive oil over medium heat until the butter melts and starts to foam. Add the sliced onions and sprinkle with the kosher salt. Toss to coat all the onions in the fat.
Reduce the heat to medium-low. Cook, stirring every few minutes, until the onions become soft, then golden, then deep amber, 20–25 minutes. If they start to brown too quickly or stick, lower the heat and add a splash of water to deglaze the pan.
Once the onions are a rich, jammy golden-brown, stir in the brown sugar and balsamic vinegar, if using. Cook for 1–2 minutes more to dissolve and lightly glaze the onions. Taste and adjust salt if needed. Turn off the heat and set aside, keeping warm.
Step 2: Preheat the Grill
While the onions are cooking, preheat your grill to medium-high heat, about 400–450°F (200–230°C). If using a gas grill, set the burners to medium-high and close the lid for 10–15 minutes to preheat fully. For a charcoal grill, light the coals and let them burn until they are mostly covered with gray ash, then arrange them in an even layer for direct grilling.
If you plan to cook indoors, you can use a cast-iron skillet or grill pan instead. In that case, wait to preheat it over medium-high heat for 3–5 minutes just before cooking the burgers.
Step 3: Season the Ground Beef
Place the ground beef in a large mixing bowl. Sprinkle the kosher salt, black pepper, garlic powder, and onion powder (if using) evenly over the meat. Drizzle in the Worcestershire sauce and add the cold water or milk if you are using it.
Using clean hands, gently mix just until the seasonings are evenly distributed. Do not overwork the meat; stop as soon as it looks fairly uniform. Over-mixing can make the burgers dense instead of tender and juicy.
Step 4: Form and Stuff the Burger Patties
Divide the seasoned beef into 8 equal portions (about 3 oz / 85 g each). Roll each portion into a ball, then gently flatten into thin patties about 4 inches (10 cm) wide. Make sure all patties are roughly the same size and thickness so they cook evenly.
Place 4 of the patties on a tray or plate. Divide the crumbled blue cheese evenly among these 4 patties, mounding it in the center and leaving a 1/2-inch (1.25 cm) border around the edges.
Top each cheese-covered patty with one of the remaining 4 patties. Gently press around the edges to seal, pinching and smoothing the seam all the way around so the cheese is fully enclosed. Then gently press the center of each patty to slightly flatten it and even out the thickness.
With your thumb, make a very shallow indentation in the center of each patty. This helps the burgers stay flatter and cook more evenly instead of puffing up in the middle.
Step 5: Chill the Patties Briefly
Place the stuffed patties on a plate or tray in a single layer. Cover loosely with plastic wrap and refrigerate for 10–15 minutes. This quick chill helps the burgers firm up, making them easier to handle on the grill and helping the seams stay sealed around the cheese.
During this time, gather and prepare your serving ingredients: split the buns, rinse and dry the lettuce leaves, and slice the tomato into thick slices.
Step 6: Grill the Burgers and Toast the Buns
Clean and oil the grill grates lightly to help prevent sticking. Place the chilled stuffed patties on the preheated grill. Close the lid and cook for about 5–6 minutes on the first side without moving them, until the bottoms are well-browned and the burgers release easily from the grates.
Flip the burgers carefully using a wide spatula. Grill for another 4–6 minutes, or until the internal temperature reaches 160°F (71°C) at the center (use an instant-read thermometer inserted into the side of the patty, trying to avoid the pocket of melted cheese). Because these are stuffed burgers, it is safer to cook them to at least 160°F.
During the last 1–2 minutes of cooking, place the split buns, cut side down, on the grill to lightly toast them until golden at the edges. Remove the buns once toasted and transfer the cooked patties to a clean plate or tray to rest.
Step 7: Assemble and Serve
Spread the bottom and/or top halves of the toasted buns with mayonnaise and Dijon mustard, to taste. Layer a leaf of lettuce on the bottom bun, then place a hot blue cheese stuffed burger patty on top.
Spoon a generous pile of warm caramelized onions over each burger patty. Add a thick slice of tomato, plus pickles or extra crumbled blue cheese if you like. Cap with the top bun.
Let the burgers rest for 2–3 minutes before biting in; the cheese will be molten and very hot. Serve immediately with your favorite sides such as fries, a simple green salad, or grilled vegetables.
Pro Tips
- Keep the meat cold: Cold beef holds its shape better and helps keep the blue cheese from leaking out. If it feels warm, pop it back in the fridge for a few minutes.
- Do not overwork the beef: Mix only until the seasonings are combined. Over-mixing compresses the meat and leads to tough burgers.
- Seal the edges well: Take your time pinching and smoothing the seams of the stuffed patties. Any gaps can become escape routes for the melted cheese.
- Control your heat: Medium-high is ideal. Too hot, and the outside may burn before the center cooks and the cheese melts; too low, and the burgers can dry out.
- Use a thermometer: Because these are stuffed burgers, checking doneness with an instant-read thermometer is the most reliable way to avoid undercooked meat or overcooked, dry burgers.
Variations
- Bacon and Blue: Add 2–4 slices of crisp cooked bacon per burger, either chopped into the blue cheese filling or layered on top with the caramelized onions.
- Stovetop Version: Cook the stuffed burgers in a hot cast-iron skillet or grill pan over medium-high heat with a little oil, 5–6 minutes per side, until they reach 160°F (71°C).
- Extra Tangy: Mix 1–2 tbsp crumbled blue cheese into the caramelized onions at the end, and add a few dashes of hot sauce or a smear of whole-grain mustard on the bun.
Storage & Make-Ahead
Make-ahead patties: You can form the stuffed burger patties up to 24 hours in advance. Keep them covered in the refrigerator on a plate or tray. For best texture, do not salt the meat more than a day ahead. Remove from the fridge about 10 minutes before cooking.
Caramelized onions: The onions can be made 3–4 days in advance. Store in an airtight container in the refrigerator. Reheat gently in a skillet over low heat with a splash of water, or in the microwave.
Leftover cooked burgers: Store in an airtight container in the refrigerator for up to 3 days. Reheat gently in a covered skillet over low heat with a tablespoon of water added to the pan, or in a 300°F (150°C) oven until warmed through. Note that the cheese center may not be as molten after reheating, but the flavor will still be delicious.
Freezing: Uncooked stuffed patties freeze well. Freeze on a tray until firm, then transfer to a freezer bag with parchment between patties. Freeze for up to 2 months. Thaw overnight in the refrigerator before grilling.
Nutrition (per serving)
Approximate values per burger with bun, caramelized onions, lettuce, tomato, mayo, and Dijon:
Calories: ~820 kcal; Protein: ~43 g; Carbohydrates: ~42 g; Fat: ~52 g; Saturated Fat: ~22 g; Fiber: ~3 g; Sodium: ~1300 mg. Values will vary based on bun type, exact blue cheese, and condiments used.
