Balsamic Portobello Burgers with Caramelized Onions & Garlic Aioli
User Reviews
4.7
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Prep Time
1 hr 15 mins
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Cook Time
10 mins
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Total Time
1 hr 25 mins
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Servings
4 (Burgers)
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Calories
465 kcal
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Course
Main Course
Balsamic Portobello Burgers with Caramelized Onions & Garlic Aioli
Description
Balsamic Portobello Burgers begin by roasting a whole head of garlic until soft and mellow, which forms the base for a creamy aioli along with soaked cashews and minced garlic. The mushrooms are cleaned, marinated with balsamic vinegar, olive oil, Italian herbs, garlic, salt, and pepper, then brushed thoroughly to absorb the tangy, herby flavors.
Caramelized onions cooked slowly in oil provide a deep sweetness that contrasts the savory mushroom. The assembled burger layers the tender, juicy mushroom caps with the caramelized onions and garlic aioli inside whole wheat buns, optionally enhanced with tomato slices and greens. The result is a rich, balanced texture featuring the umami mushrooms, silky sauce, and soft yet sturdy bread.
This burger suits both casual and vegetarian-friendly meals, adding complexity through its marinade and garlic elements. Using roasted garlic in the aioli mellows its strength, making it creamy and approachable. The recipe encourages using organic and whole grain components for freshness and texture variety.
Adapting this recipe allows substitution of almond milk for water in the aioli for creaminess or choosing lettuce wraps or gluten-free buns as needed. It’s recommended to soak cashews properly and allow the garlic to cool before blending for best results.
Ingredients
GARLIC AIOLI
- 1 head garlic (to roast)
- 3/4 cup cashew nuts raw
- 2 cloves garlic omit for less intense garlic flavor, minced
- 1 Tbsp avocado oil or olive oil
- 1/3 cup water (or sub unsweetened almond milk for creamier consistency)
- salt to taste
- black pepper to taste
BURGERS
- 4 medium-large portobello mushrooms (organic when possible)
- 3 Tbsp avocado oil or olive oil
- 1/4 cup balsamic vinegar
- 1 Tbsp Italian seasoning (dried basil + oregano)
- 2 cloves garlic 2 cloves yield ~1 Tbsp or 6 g, minced
- 1 healthy pinch salt
- 1 healthy pinch black pepper
CARAMELIZED ONIONS
- 1 Tbsp avocado oil or olive oil
- 1 medium onion white or yellow, peeled and sliced into 1/4-inch rings
FOR SERVING
- 4 whole wheat hamburger buns (ensure vegan-friendly as needed // sub lettuce wraps or GF buns for gluten-free)
- 2 ripe tomato optional // organic when possible, sliced
- lettuce optional, or greens of choice
Instructions
- Preheat oven to 400 degrees F (204 C) and cut off the very top of a head of garlic. Drizzle with a little oil, sprinkle with sea salt, and loosely wrap in foil. Set directly on an oven rack and bake for 1 hour. Let cool before use. Note: To save time, you could buy roasted garlic, or sub the head of roasted garlic for 3-4 additional cloves raw garlic and proceed as instructed.
- In the meantime, place cashews in a bowl and cover with just boiling water. Let sit uncovered for 1 hour. Then drain and rinse thoroughly.
- While cashews are soaking, use a damp washcloth or paper towel to clean the mushrooms by wiping away any dirt and removing the stems. Place stem side up on a rimmed baking sheet or 9x13-inch baking dish.
- To a small mixing bowl, add avocado oil, balsamic vinegar, Italian seasoning, minced garlic, salt, and pepper. Whisk to combine, then pour over the mushrooms and use a pastry brush to distribute the marinade. Flip the mushrooms over and brush the other side, then flip back over to stem-side-up position. Set aside, uncovered at room temperature, to marinate (at least 30 minutes).
- Add your drained, soaked cashews to a small blender. Take your roasted head of garlic and press out the softened garlic by squeezing from the base up until all of the garlic is extracted.
- To the blender also add fresh garlic, avocado oil, water (or almond milk), and a pinch each salt and pepper. Blend on high until creamy and smooth, scraping down sides as needed. Taste and adjust seasonings as needed, adding more olive oil or water for creaminess or salt for saltiness. Transfer to a serving dish and set aside.
- To caramelize onions, heat a large skillet over medium heat. Once hot, add 1-2 Tbsp avocado oil, the sliced onion, and a pinch of salt. Sauté, stirring frequently, until light golden brown and very soft (see photo). Remove from skillet and set aside.
- Return the skillet to the stovetop (or heat a grill and lightly oil grilling surface). Once hot, add portobello mushrooms — only as many as will fit comfortably in the pan — and sauté for about 3-6 minutes on each side, or until the mushrooms are deep golden brown on the edges and softened/reduced in size (see photo). While cooking, brush with any leftover marinade for extra flavor.
- At this time, prepare any serving items, such as browning hamburger buns on the skillet (or grill), slicing tomato, or chopping greens.
- To serve, add a generous spoonful of garlic aioli to each bun and top with aioli, then tomato, lettuce (or greens), mushrooms, onions, and more aioli on top of the bun.
- Enjoy immediately. Store leftover mushrooms separately in the refrigerator up to 2-3 days, though best when fresh. Aioli will keep in the refrigerator for 7-10 days.
Notes
- Roast the garlic head wrist carefully for one hour to develop mellow flavor for the aioli.
- Soak cashews in hot water for an hour to ensure smooth blending into creamy garlic aioli.
- Clean portobello mushrooms gently with a damp cloth to preserve texture before marinating.
- Leftover aioli can be refrigerated and used on other sandwiches or as a dip.
- Substitute ingredients like almond milk for water can modify aioli texture and flavor.
- Nutrition is estimated without optional ingredients and uses avocado oil.
Nutrition Information
Show DetailsNutrition Facts
Serving: 4(Burgers)
Amount Per Serving
Calories 465 kcal
% Daily Value*
| Serving | 1burgers | |
| Calories | 465 | 23% |
| Carbohydrates | 40.6g | 14% |
| Protein | 13.2g | 26% |
| Fat | 29.6g | 46% |
| Saturated Fat | 4.3g | 22% |
| Sodium | 251mg | 10% |
| Potassium | 716mg | 15% |
| Fiber | 5.5g | 22% |
| Sugar | 9.1g | 18% |
* Percent Daily Values are based on a 2,000 calorie diet.
User Reviews
Overall Rating
4.7
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