4 Portobello mushroom caps, gills removed and chopped
2 bunches of lettuce
1 bunch of sprouts
1 garlic clove, minced
2 TSPs rice wine vinegar
5 whole-grain burger buns
2 TBSP canola oil
25g red onion, chopped
90g quinoa, cooked
3 green onions, chopped
For the rosemary mayo
1 TSP fresh rosemary, finely chopped
Kosher salt, to taste
1 TSP lemon juice
Toss mushrooms with a tablespoon of oil, walnuts, minced clove of garlic, pepper, and salt in a shallow baking dish. Spread evenly and bake in a preheated oven at 190 C, until mushrooms are tender, for about 20 minutes. Once done, take it out and set aside. Turn off the oven.
Add the mushroom mixture to a processor along with chopped green onions, red onion and 2 TSPs of rice wine vinegar. Pulse until smooth, then transfer to a bowl.
Add cornstarch and cooked quinoa until blended. Refrigerate for 2 hours, covered with plastic wrap.
After two hours, form 5 patties from the mixture. Preheat a TBSP of oil in a non-stick skillet.
Cook patties until well-browned, for 5 minutes or more, turning once. Do in batches.
Place patties in a foil-lined baking sheet and bake in a preheated oven at 190 C, for about 10 minutes.
Meanwhile, prepare rosemary mayo by combining all 4 ingredients in a bowl.
Serve mushroom-quinoa burgers on buns along with rosemary mayo. Garnish with tomato, lettuce and sprouts.