These black bean burgers are the best we've ever tasted! Perfectly seasoned and not mushy.
Preheat oven to 325°F. Spread beans out evenly on a parchment paper lined baking sheet. Bake for 15 minutes, until slightly dried. Raise temperature to 375º and let oven preheat if cooking burgers in oven.
Blend walnuts in food processor until semi-fine texture.
Sauté oil, onion, jalapenos, and garlic over medium heat for 5 minutes, or until onions and peppers are soft. Add along with rest of ingredients to bowl. Blot out some of the oil with a paper towel. Add mixture from the previous step to walnuts in the food processor and blend. Add beans and blend again. Leave some chunks of beans for texture.
Form 1/3 cups of bean mixture into patties and place on a baking sheet lined with parchment paper. Bake for 10 minutes. Flip over and bake for another 10 minutes. Alternatively, cook burgers in an oil-greased skillet for 10 minutes on each side.
Serve on brioche bun with lettuce, onions, tomatoes, spicy mayo, or whatever condiments you like.