Portobello Sliders

Bread alternatives are having a moment. Between sweet potato toast, avocado buns, and cauliflower crust pizza, it seems like just about any substitution is fair game. Next time you’re craving a burger, try these sliders with roasted Portobello mushroom caps for buns—they’re the perfect size and shape! And given their hearty, almost meaty flavor, we like to skip the burger patty and fill the sandwiches with all the fixings: caramelized onions, goat cheese, tomatoes, lettuce, and bacon. 


For the portobello “buns”: 

4 tablespoons balsamic vinegar

1/3 cup coconut aminos

1/3 cup olive oil

4 cloves garlic, chopped

1 tablespoon lemon juice

1 teaspoon rosemary

1 teaspoon dried oregano

2 teaspoons dried thyme

Sea salt and freshly ground pepper

8 Portobello caps

For the caramelized onions:

2 tablespoons olive oil

2 yellow onions, thinly sliced

For the toppings:

Goat cheese

Tomatoes, sliced

Avocados, sliced

Romaine lettuce

Cooked bacon


1. Marinate the mushrooms

2. Mix balsamic vinegar, coconut aminos, olive oil, garlic, lemon juice, rosemary, oregano, thyme, and salt and pepper in a baking dish. Remove stems from mushrooms, add them to the dish, and let marinate for 1 hour.

3. Caramelize the onions

Meanwhile, heat 2 tablespoons olive oil in a large skillet over medium-high heat. Cook onions, stirring frequently, about 5 minutes, then turn heat down to low and cook until caramelized, about 30 minutes, stirring occasionally.

4. Bake the mushrooms

Preheat oven to 400 degrees and line a baking sheet with parchment paper. Remove mushrooms from marinade and place on baking tray. Roast in oven 20 minutes.

5. Assemble the sliders

Top the inside of one half of the mushroom caps with the caramelized onions, following with goat cheese, tomato slices, avocado, romaine, and bacon. Top with the remaining mushroom caps to serve.

Yield: 4 servings

Active Time: 20 minutes

Total Time: 1 hour and 30 minutes