Preheat the oven to 325°F. Drain the beans in a colander and rinse them under running water until all foam is gone, then let them drain well. Spread the beans on a baking sheet lined with parchment paper and bake for 15 minutes, until the beans are slightly dried out and some have split open.

Peel and finely dice the onion and garlic cloves. Slice the jalapeño in half lengthwise, remove the seeds if desired, and cut into thin strips. Heat the oil in a pan and sauté the onion, garlic, and jalapeño with a pinch of salt until the onions are translucent. Remove from heat and let cool briefly.

Place the beans, sautéed vegetables, egg, spices, tomato paste, and miso in a large bowl. Mash together with a potato masher or fork until smooth but still slightly chunky, then stir in the breadcrumbs. Season the mixture generously with salt and pepper, and stir in the juice of ¼ lime.

Shape the mixture into four equal patties and place them on a baking sheet lined with parchment paper. Meanwhile, preheat the oven to 400°F. Bake the patties for a total of 20 minutes, flipping them halfway through.

Alternatively, you pan-fry the patties: Heat a little oil in a pan and fry the patties over medium-high heat for about 3–4 minutes on each side, until golden brown.