Ingredients
Method
Stir ½ cup ketchup, 2 Tbsp. organic sugar, 1 Tbsp. apple cider vinegar, 1 Tbsp. hot chili sauce, and ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt in small bowl until combined; set glaze aside.
Place a rack in middle of oven; preheat to 375°. Heat 2 Tbsp. vegetable oil in a large skillet over medium-high. Cook 8 oz. crimini mushrooms, trimmed, sliced ½" thick, and 2 medium onions, sliced ½" thick, tossing occasionally, until softened and golden brown, 5–7 minutes. Add 2 Tbsp. ketchup and 2 Tbsp. soy sauce, preferably low-sodium, and cook, stirring often, until soy sauce is evaporated and ketchup has darkened in color, about 2 minutes. Let cool 10 minutes.
Transfer mushroom mixture to a food processor. Add 2 Tbsp. vegetable bouillon paste, 1 Tbsp. garlic powder, 2 tsp. dried oregano, 2 tsp. freshly ground pepper, 2 tsp. yellow mustard, and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt; pulse, scraping down sides as needed, until mixture is finely chopped and almost a paste. Transfer to a large bowl.
Add two 8.8-oz. packages precooked brown rice or 1¾ cups cooled cooked brown rice to food processor and pulse until grains are about the size of sesame seeds; add to large bowl with mushroom mixture. Add one 15-oz. can pinto beans, rinsed, to food processor and pulse, scraping down sides as needed, until a coarse purée forms; add to large bowl. Add ¾ cup quick-cooking oats to large bowl; mix with a rubber spatula until ingredients are evenly distributed.
Transfer meatloaf mixture to a parchment-lined rimmed baking sheet and form into a roughly 10"x5" log; smooth surface. Brush half of reserved glaze over top and sides.
Bake meatloaf until glaze looks matte, 20–25 minutes. Brush remaining glaze over. Bake until glaze is set, surface is tacky, and a tester or paring knife inserted into the center of meatloaf comes out hot, 20–25 minutes. Let rest 15 minutes before slicing.