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Straight on view of a Mushroom Swiss Burger with grilled onions on a cutting board on a dark wood surface with a burger and a bottle in the background, and a dark grey textured backdrop.

Mushroom Swiss Burgers with Tarragon Aioli


A Mushroom Swiss Burger is a classic for a reason. I like to add grilled onions and a special aioli to top it off.


  • 1 1/2 pounds 80/20 ground beef
  • 6 ounces Swiss cheese, thinly sliced, or 4 slices of pre-cut Swiss cheese
  • 1/2 small white or yellow onion, sliced into rings
  • 4 burger buns (I used brioche)
  • Kosher salt and fresh cracked pepper

Tarragon Aioli (optional):

  • 1 large egg yolk
  • 7 tablespoons vegetable oil
  • 1 tablespoon extra virgin olive oil
  • 1 teaspoon lemon juice
  • 1/2 teaspoon sherry or red wine vinegar
  • 1 clove garlic, finely grated
  • 1 teaspoon finely chopped tarragon

Marinated Mushrooms:

  • 12 ounces baby portabella mushrooms, trimmed, whole or halved if large
  • 1 1/2 tablespoons extra virgin olive oil
  • 1 1/2 teaspoons balsamic vinegar, plus more as needed
  • Olive oil, as needed


  1. Make aioli. Place a towel underneath a small bowl to prevent it from moving around. Add yolk to bowl and season lightly with salt. Slowly drizzle in vegetable oil, while constantly whisking, starting with only a few drops at a time. You may pick up speed as emulsified mixture thickens. Drizzle in olive oil and whisk to combine. Stir in lemon juice, vinegar, grated garlic and chopped tarragon. Taste and adjust seasoning as needed. Refrigerate until ready to use.
  2. Marinate mushrooms: Add mushrooms to a bowl. Toss with oil, vinegar, salt and pepper. Marinate at room temperature for about 30 minutes, or until ready to grill.
  3. Shape burgers. Divide meat into 4, 6oz patties. Form patties slightly wider than buns and create a slight indent in the center to account for puffing during cooking.
  4. Grill mushrooms. Preheat grill pan or outdoor grill over medium-high heat. Lightly oil grates. Remove mushrooms from marinade, shaking off any excess, and place on grill. You may need a basket for an outdoor grill so the vegetables don’t fall through the cracks. Toss sliced onion with oil and salt, and place on grill. Cook vegetables about 3-5 minutes per side or until charred and cooked through. Taste mushrooms and onions for seasoning and adjust, if needed. Slice mushrooms. 
  5. Toast buns. Preheat grill pan, outdoor grill, cast-iron skillet or nonstick pan over medium-high heat. I prefer to use either an outdoor grill or cast iron. Split buns and toast cut-side down for about 1-2 minutes or until browned in spots.
  6. Cook burger. Season burger aggressively with salt and pepper on both sides and place on grill. Cook about 2-2 ½ minutes per side for medium-rare, or for an additional 1-3 minutes total if you prefer it medium to well-done. After flipping, place cheese on burgers and cover with a lid for remaining cooking time to help melt cheese. Transfer burgers to a plate.
  7. Serve. Slather the bottom buns with aioli. Place burger patty on top. Add mushrooms and onions. Slather top buns with more aioli, if desired. Top and enjoy.


For an easier version of aioli, mix store bought mayo with a little grated garlic, lemon juice and tarragon.

If you don’t have a microplane or fine grater for the garlic, you may also use a garlic press.

Alternative spreads include plain mayo, ketchup and mustard.

You can use button mushrooms or shitakes in place of baby portabellas.

  • Prep Time: 45 minutes
  • Cook Time: 15 minutes
  • Category: Main
  • Method: Grill
  • Cuisine: American


  • Serving Size: 1 burger with toppings
  • Calories: 800
  • Sugar: 8g
  • Sodium: 715mg
  • Fat: 52g
  • Saturated Fat: 34g
  • Unsaturated Fat: 18g
  • Trans Fat: 0g
  • Carbohydrates: 31g
  • Fiber: 3g
  • Protein: 55g
  • Cholesterol: 177mg

Keywords: mushroom swiss burger, mushroom burger, burger with mushrooms and onions