You are here: Home » Recipes » Grilled Portobello Burgers with Caramelized Onions Grilled Portobello Burgers with Caramelized Onions Recipe by Our Cookbook Collection Yield 4 servings Substitute greasy beef for a delicious portobello mushroom for a great burger option. Jackie Sobon | VeganYackAttack.com Grilled portobello burger PrintEmail Ingredients 4 portobello mushroom caps1 tablespoon fresh rosemary1/3 cup liquid aminos or soy sauce2 1/2 cups water2 tablespoons olive oil2 white onions, sliced into rings2 teaspoons balsamic vinegar2 1/2 cups baby arugula tomato slices dijon mustard avocado slices (optional)4 burger buns, pita pockets or 8 slices of bread2 cups shredded jicama2 cups shredded Pink Lady apple1/2 cup fresh-squeezed orange juice pinch salt Instructions Clean the mushroom caps and remove stems. Place the caps in a shower dish or Ziploc bag; mix the liquid aminos and rosemary with the water and pour it over the mushroom caps. Marinate for at least 2 hours. Heat the olive oil in a medium-sized pan over medium heat. Once hot, introduce onion slices to the pan and sauté them until they begin to become clear, stirring occasionally. Add balsamic vinegar and to the onion sauté and continue to cook them until they are limp and most of the liquid has been cooked out. Heat your grill with a medium-high flame and take the portobello mushroom caps out of the marinade. Make sure to drain them of excess liquid, and grill them for 10-12 minutes on each side or until they have shrunken in size and softened. Toast your buns, place mushroom cap on the bottom and top it with the caramelized onions. Place uncooked baby arugula, tomatoes, avocado and Dijon mustard on top of the onions, followed by the top bun. For the salad, use a julienne peeler or grater to shred the jicama and apple. Toss them together with the orange juice in a bowl and serve chilled. Jackie Sobon of the food blog Vegan Yack Attack, is passionate about creating innovative and tasty recipes that cater to the taste buds of everyone, vegan or not. On top of running her food blog, she also contributes to the Examiner, One Green Planet and the Vegan Voice. In her free time, you can find her dreaming up recipes while hiking, doing yoga, or cycling; talk about preemptive action!