Finely mince the mushrooms into 1/8-inch pieces to mimic meat texture, then cube the onions, carrots, and celery. Start by cooking the mushrooms in a large pan over medium-high heat for 10 minutes to release their moisture and develop deeper flavor. Add oil and salt, then cook for 5 minutes more until they begin to caramelize slightly. In a separate pan, sauté the onions, carrots, and celery in oil over medium heat for 25 minutes until very soft and golden. During the last minute of cooking, add the freshly minced garlic and stir constantly to bloom its flavor without burning it. Remove both pans from heat and let the vegetables cool for 10-15 minutes before proceeding.

In a small bowl, whisk together the soy sauce, vegan Worcestershire, miso paste, tomato paste, vinegar, paprika, nutritional yeast, and cayenne until fully incorporated into a cohesive sauce. This combination creates the umami-rich seasoning that gives the patties their meaty depth. Pour the sauce over the cooled vegetables from Step 1 and stir until evenly distributed throughout.

Transfer the vegetable and sauce mixture to a food processor and pulse until chunky—you want texture and irregularity here, not a smooth paste, as this mimics ground meat. Pour the processed mixture into a large bowl and fold in the drained chickpeas, cooked rice, ground cumin, and liquid smoke. I find that adding the binder ingredients gradually helps you achieve the right consistency without over-mixing. Sprinkle the potato starch and wheat gluten over the top, then knead the mixture with your hands for 2-3 minutes until it becomes firm and holds together well. Add the psyllium husk and methylcellulose, which help create the crispy exterior crust when cooked. Taste and adjust seasoning with salt and black pepper as needed.

Refrigerate the mixture for 30 minutes to help it firm up and become easier to work with. Once chilled, portion out 2 oz of the mixture per patty and roll into balls. Coat each ball generously with panko breadcrumbs, pressing gently so they adhere evenly. I like to use Kikkoman panko for its lighter, airier crunch that stays crispy even after smashing.

Heat a large skillet over medium-high heat and lightly oil it. Place a breaded patty into the pan and immediately cover it with a piece of parchment paper, then use a heavy spatula or press to firmly smash it flat to about 1/4-inch thickness. This smashing creates maximum surface contact for crust development. Cook for 2 minutes without moving until the bottom is deeply browned and crispy, then carefully flip, remove the parchment, and cook the other side for 2 minutes until equally golden and firm.

While the final batch of burgers cooks, place burger buns cut-side down in a separate pan over medium heat for 1-2 minutes until lightly toasted and golden. Place each smashed burger patty on a toasted bun bottom and add your desired toppings such as lettuce, tomato, pickles, and sauce.