Some days we just want a big, juicy burger—but without the bun and the bloat. That’s exactly why we love this recipe. These keto grilled portobello burgers swap the traditional bun for smoky, grilled mushroom caps that bring their own savory, umami-rich magic. They hold together beautifully, soak up flavor like a dream, and turn a basic burger into something bold and totally satisfying.
We started making these when we were grilling out and realized we had everything but buns. Turns out, portobello caps were the upgrade we didn’t know we needed. Add a juicy beef patty, melted cheddar, creamy avocado, crisp lettuce, and a slather of sugar-free BBQ sauce—and suddenly it’s not just a workaround, it’s better.
This is one of those meals that satisfies that deep burger craving while keeping things totally clean and keto. Whether you’re tossing them on the grill or using a grill pan indoors, these burgers never disappoint.
Keto Grilled Portobello Burgers (No Bun)
These keto grilled portobello burgers are everything you love about a juicy burger—minus the bun. Smoky mushroom caps hold it all together with flavor and texture, making this low-carb recipe a BBQ staple.
Ingredients
For the Portobello Buns:
For the Burger Patties:
Toppings (Optional but Recommended):
Instructions
Prep & Grill the Mushrooms:
-
Clean the mushrooms: Gently scrape out the gills with a spoon. Brush both sides with olive oil and sprinkle with salt and pepper.
-
Grill: Place mushrooms gill-side down on a medium-high grill or skillet. Cook for 4–5 minutes per side until tender and grill-marked. Set aside on paper towels to absorb extra moisture.
Cook the Burger Patties:
-
Season the meat: In a bowl, mix ground beef with salt, pepper, garlic powder, and BBQ sauce. Form into 4 even patties.
-
Grill the patties: Cook on a hot grill or skillet for 3–4 minutes per side, or until desired doneness. Add cheese in the final minute if using. Let rest for 3 minutes before assembling.
Assemble the Burgers:
-
Build it: Place one grilled mushroom cap (gill-side up) as the base. Add lettuce, the burger patty, avocado slices, onions, a smear of mayo or BBQ sauce, and pickles. Top with another mushroom cap.
-
Serve hot: Serve immediately with napkins—it’s a deliciously messy one!
Nutrition Facts
Servings: 4 ServingCalories:480kcalTotal Fat:34gSaturated Fat: 11gTotal Carbohydrate:7gDietary Fiber: 3gSugars: 2gProtein:32g
Note
Substitutions & Variations
- No beef? Use ground turkey, lamb, or a veggie patty.
- Dairy-free? Skip the cheese or use a dairy-free alternative.
- Spicy version? Add jalapeños or spicy chipotle mayo.
- Extra toppings: Try sautéed onions, grilled peppers, or crispy bacon.
- Knife-and-fork option: Skip the top mushroom and eat it open-faced.
