How to Make It
Peel and finely chop the tomatoes and let them drain in a sieve set over a bowl. Meanwhile, in a medium bowl, mash the beans with 1 tablespoon of the herbs, the egg yolk, onion, garlic and chili powder; leave a few beans whole for texture. Season with salt and pepper.
In a small bowl, beat the egg white until it holds soft peaks, then fold it into the mashed beans. Using moistened hands, form the mixture into 8 patties, each about 1/2 inch thick. Coat the patties well with the bread crumbs.
In a large heavy skillet, heat 1 1/2 tablespoons of the oil. Fry 4 of the patties over moderately high heat until golden brown, about 2 minutes per side. Transfer to a baking sheet and keep warm in a low oven. Wipe out the skillet and repeat with the remaining oil and bean patties.
In a small bowl, toss the chopped tomatoes with the remaining herbs and the lemon juice. Season with salt and pepper. Serve the bean cakes topped with the chopped tomatoes.