3/4 cup dried brown lentils, rinsed
2 1/2 tsp. sea salt, divided
3/4 cup bulgur wheat or brown rice
2 Tbsp. olive oil, coconut oil or organic pasture butter
2 medium onions, finely chopped (2 cups)
1 large celery rib, finely chopped (1/2 cup)
1 small leek, white and light green parts only, finely chopped (1/2 cup)
2 medium garlic cloves, minced or pressed through garlic press (2 tsp.)
1 lb. cremini or white mushrooms, cleaned and sliced about 1/4 inch thick (about 6 1/2 cups)
1 cup raw, unsalted cashews
1/3 cup Veganaise
2 cups Panko bread crumbs or crushed corn flakes, rice Chex, rice cakes or gluten-free bread crumbs, such as Glutino®
Ground black pepper (to taste)
Bring 3 cups water, lentils and 1 tsp. salt to boil in medium saucepan over high heat; reduce heat to medium-low and simmer, uncovered, stirring occasionally, until lentils are just beginning to fall apart, about 25 minutes. Drain in fine mesh strainer. Line baking sheet with triple layer paper towels and spread drained lentils over towels. Gently pat lentils dry with additional paper towels; cool lentils to room temperature.
While lentils simmer, bring 2 cups water and 1/2 tsp. salt to a boil in small saucepan. Stir bulgur wheat into boiling water and cover immediately; let stand off heat until water is absorbed, 15-20 minutes. Drain in fine mesh strainer; use rubber spatula to press out excess moisture. Transfer bulgur to medium bowl and set aside. If you are using brown rice, bring 1 1/2 cup water, 1/2 tsp. salt and 3/4 cup brown rice to a boil. Turn heat down to simmer, cover and cook until all liquid is gone, 30-40 minutes.
Heat 2 Tbsp. oil in 12 in. skillet over medium-high heat until shimmering. Add onions, celery, leek, garlic and mushrooms; cook, stirring occasionally, until veggies begin to brown, about 10 minutes. Spread veggie and mushroom mixture on a baking sheet; cool to room temperature, about 20 minutes.
Process cashews in a food processor until finely chopped, about 15 pulses (do not wash food processor blade or bowl); stir into bowl with bulgur along with cooled lentils, veggie-mushroom mix and Veganaise. Transfer half of mixture to now-empty food processor and pulse until coarsely chopped, 15-20 pulses; mixture should be cohesive but roughly textured. Transfer processed mixture to large bowl; repeat with remaining unprocessed mixture and combine with first batch. Stir in breadcrumbs or pulverized cereal, 1 tsp. salt and pepper to taste. Line baking sheet with paper towels. Divide mixture into 12 portions, about 1/2 cup each, shaping each into tightly packed patty, 4 in. in diameter and 1/2 in. thick; set patties on baking sheet; paper towels will absorb excess moisture.
To cook burgers on the grill: build medium-hot charcoal fire or preheat gas grill on high. Using tongs, wipe grate with wad of paper towels dipped lightly in vegetable oil. Grill burgers without moving them, until well browned, about 5 minutes; flip burgers and continue cooking until well-browned on second side, about 5 minutes.
To cook burgers on the stovetop: heat 2 Tbsp. oil in 12 in. nonstick skillet over medium-high heat until shimmering; cook burgers, four at a time, until well-browned, about 4 minutes per side, lowering heat to medium if browning too quickly. Repeat with additional oil and burgers. Serve.
Serving suggestions: Serve on a whole grain hamburger bun with lettuce, tomato, onion, and other veggies, serve over green salad as croquets, serve over brown rice with stir-fried vegetables, or eat all by itself!