- Heat 1 tablespoon of olive oil over medium heat in a non-stick pan. Add onion slices and sauté for 5 minutes, until onions begin to soften and brown. Add mushrooms and remaining tablespoon of olive oil. Sauté for 7-8 minutes longer, stirring regularly. Turn heat off and let cool down for 5 minutes.
- Add chickpeas, panko, dried seasonings, soy sauce and egg to a food processor. Blend until thoroughly mixed and chickpeas are smooth, stopping to scrape sides if needed. Add walnuts and onion/mushroom mixture. Pulse until walnuts and sautéed vegetables are broken up into tiny pieces.
- Transfer mixture to a mixing bowl. Use hands to form into 4 patties. Place onto a small parchment paper lined tray and transfer to freezer while heating grill.
- Grease outdoor grill with cooking spray and heat to 400ºF. Add patties to hot grill and grill for 6 minutes. Gently flip using a spatula and cook 6 minutes longer. Serve hot on lettuce or a bun with your favorite burger fixings.