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Image of a Plate Containing a Mushroom Burger with Horseradish Aioli

Mushroom Burger with Horseradish Aioli

  • Author: Krista
  • Prep Time: 5 minutes
  • Cook Time: 26 minutes
  • Total Time: 31 minutes
  • Yield: 4 burgers 1x
  • Category: Dinner
  • Method: Grill
  • Cuisine: American
  • Diet: Gluten Free


This Mushroom Burger with Horseradish Aioli is a delicious gluten free burger recipe! It’s made with caramelized onions and topped with a creamy homemade horseradish aioli!


  • 1.25 lbs. lean ground beef
  • salt & pepper to season
  • 2 tablespoon grape seed oil
  • 1 large sweet onion, sliced
  • 8 oz. sliced white mushrooms
  • 2 teaspoons fresh thyme
  • 1/2 tablespoon stone ground mustard
  • salt & pepper to taste
  • 1 large beefsteak tomato, cut into 4 thick slices
  • 2 cups of greens (I used a baby spinach & kale mixture)

Horseradish Aioli:

  • 1/3 cup mayo
  • 1 1/2 tablespoons prepared horseradish
  • 1 tablespoon stone ground mustard
  • 1 tablespoon lemon juice


  1. Preheat grill to medium high heat, about 375-400 degrees.
  2. Form four 1/3 lb. patties. Season both sides with salt and pepper. Set aside.
  3. Heat a large saute pan to medium high heat. Add grape seed oil and onions to the pan. Saute for 5-7 minutes, until slightly caramelized. Add in the mushrooms. Saute until brown, approximately 5-7 minutes. Season with salt & pepper. Add in the fresh thyme and mustard. Stir to mix all the ingredients together. Cook for another 2 minutes. Remove from heat.
  4. In a small bowl, add mayo, horseradish, 1 tablespoon of stone ground mustard, and lemon juice. Stir till smooth and everything is mixed. Set aside.
  5. Add the burger to the grill. Grill each side for 4-5 minutes.
  6. Assemble the burgers: 1 slice of tomato, 1/2 cup of greens, burger, 1-2 tablespoons of horseradish aioli, 2-3 tablespoons of mushroom onion mixture.
  7. Devour!


  • Serving Size: 1 burger
  • Calories: 423
  • Sugar: 4 g
  • Sodium: 603 mg
  • Fat: 27 g
  • Saturated Fat: 7 g
  • Carbohydrates: 11 g
  • Fiber: 2 g
  • Protein: 31 g
  • Cholesterol: 105 mg

Keywords: mushroom burger, mushroom burger recipe, horseradish aioli, bunless burger, healthy burger, gluten free burger, grilling recipe, easy grilling recipe, summer grilling recipe