Take this list with you to any of our 8 supermarkets:
Bring the beans, bay leaf and black pepper to a simmer in a large pot, and cook the until completely tender, then season with salt. Let the beans sit for about ten minutes in the seasoned water, then drain.
In a pan, cook the onions in the olive oil until they are slightly caramelised.
In a large bowl, mix the beans together all the ingredients, except for the breadcrumbs. Transfer to a food processor and blend. Then add the breadcrumbs.
Divide the burger mix into patties and fry in a pan or oven.
Serve with the caramelised onions in a burger.