Drain the beans, put them in a bowl and mash roughly with a fork.
Chop the spring onions and fry them in 1 Tbsp of oil until soft.
Meanwhile, finely chop the mushrooms, then add the onion and stir for 5 minutes.
Add the mushroom mixture to the beans.
Blanch the broad beans in hot water for 2 minutes, rinse with cold water, then add to the bean mixture.
Stir in the Worcestershire sauce, tomatoes and oatmeal. Season with salt and pepper, mix well.
Form 4-6 balls from the mixture and press them slightly flat between your palm.
Heat the remaining oil and cook the patties on both sides for 5 or 6 minutes or until golden brown.
Cut the buns in half, toast or grill them until lightly charred. Spread some mayonnaise on the bottom half, followed by lettuce leaves, tomato slices or coleslaw. Place the burger on top and cover with the other half of the bun.