1 can (18oz/540ml) black beans, drained and rinsed
1 cup (180g) cooked brown rice
¾ cup (70g) panko breadcrumbs
1 teaspoon (5g) ground cumin
½ teaspoon (3g) smoked paprika
1 tablespoon (15g) Dijon mustard
2 tablespoons (30ml) canola oil
12 slider buns
Heat 1 teaspoon (5ml) olive oil over medium heat in a large non-stick skillet.
Add onions and garlic and season with salt and pepper. Cook until softened, about 3 minutes.
Add remaining olive oil and mushrooms. Cook until mushrooms start to brown, about 5 minutes.
Transfer mixture to the bowl of a food processor and pulse until finely chopped. Scrape mixture into a large bowl.
Pulse walnuts in food processor until very finely chopped. Add to mushroom mixture.
Add beans and rice to food processor and pulse until the mixture resembles a coarse puree. Add to mushroom mixture with breadcrumbs, cumin, paprika, 1 teaspoon (5g) of salt, and ½ teaspoon (3g) of pepper. Stir to combine. Add Dijon and egg; stir to combine. Form mixture into 12 equal patties, a generous 1/2-inch (1 ½ cm) thick and place on a plate or rimmed baking sheet.
Heat 1 tablespoon (15ml) canola oil in same pan over medium-high heat. Working in batches of 6, fry patties until golden and crispy, about 5 to 7 minutes, flipping halfway. Serve on slider buns topped with your favourite burger toppings and condiments.