Vegetarian Shack Burger

Satisfy your burger craving with this hearty and flavorful Vegetarian Shack Burger, a plant-based twist on the classic Shack Burger that’s as satisfying as it is delicious! Juicy grilled portobello mushroom caps take center stage, marinated in a savory blend of olive oil, soy sauce, garlic, and spices for a burst of umami flavor. Topped with melty sharp cheddar cheese and nestled in a perfectly toasted brioche or potato bun, this burger is elevated with a creamy homemade shack sauce—a tangy medley of mayo, ketchup, pickle relish, and mustard. Fresh, crisp lettuce, ripe tomato, and sweet red onion add layers of texture and freshness, making every bite an irresistible combination of savory, smoky, and tangy goodness. Quick to prepare in just 35 minutes, this vegetarian burger is perfect for summer grilling or a cozy dinner at home. Packed with bold flavors and easy-to-source ingredients, this recipe is a must-try for burger lovers and vegetarians alike!

Nutriscore Rating: 62/100

Prep Time:20 mins

Cook Time:15 mins

Total Time:35 mins

Servings: 4

Ingredients

• 4 large caps portobello mushrooms
• 4 tablespoons olive oil
• 2 tablespoons soy sauce
• 2 cloves, minced garlic
• 0.5 teaspoon salt
• 0.5 teaspoon black pepper
• 4 slices sharp cheddar cheese
• 4 pieces brioche or potato buns
• 0.5 cup mayonnaise
• 0.25 cup ketchup
• 2 tablespoons pickle relish
• 1 tablespoon yellow mustard
• 4 large lettuce leaves
• 1 large, sliced tomato
• 0.5 medium, sliced red onion

Directions

Step 1

Preheat your grill or grill pan over medium-high heat.

Step 2

In a small bowl, whisk together olive oil, soy sauce, minced garlic, salt, and pepper.

Step 3

Brush both sides of the portobello mushroom caps with the marinade mixture.

Step 4

Place the mushrooms on the grill, gill side down first, and cook for about 5 minutes per side, or until the mushrooms are tender and have grill marks.

Step 5

Place a slice of cheddar cheese on each mushroom cap during the last minute of grilling, so the cheese melts.

Step 6

While the mushrooms are grilling, toast the buns on the grill until golden brown.

Step 7

In another bowl, mix together mayonnaise, ketchup, pickle relish, and yellow mustard to create the shack sauce.

Step 8

Assemble the burgers by spreading the shack sauce on both the top and bottom buns.

Step 9

Place the grilled mushroom cap with melted cheese on the bottom bun.

Step 10

Top with a lettuce leaf, sliced tomato, and sliced red onion.

Step 11

Place the top bun over the stack and serve immediately.

Nutrition Facts

Serving size	(1206.2g)

Amount per serving	% Daily Value*
Calories	2182.6

Total Fat 182.4g	0%
Saturated Fat 40.9g	0%
Polyunsaturated Fat 5.5g
Cholesterol 237.6mg	0%
Sodium 5789.5mg	0%
Total Carbohydrate 103.2g	0%
Dietary Fiber 15.2g	0%
Total Sugars 48.7g
Protein 51.1g	0%

Vitamin D 1.5IU	0%
Calcium 901.7mg	0%
Iron 5.1mg	0%
Potassium 2787.6mg	0%

*The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.

Source of Calories

Fat: 72.7%

Protein: 9.0%

Carbs: 18.3%