This is my aunt's recipe. Like all of her recipes, it's very customizable to suit your taste.
To start with, choose your beans. You may choose all black beans if you wish. I like a 50/50 mix of black beans and kidney beans.
Choose your veggies, also according to your taste. Shred or finely chop them. Once chopped the veggies should match the volume of the beans. I like to use roughly equal amounts of broccoli, onion, and shredded carrot.