Mexican Beef Cemita Poblana | Crispy Street Food Sandwich

Slice the red onion into thin rings, place in a small bowl, and drizzle with the freshly squeezed juice of half a lime and a pinch of fine salt. Let it sit for 15 minutes to soften nicely and lightly pickle.

Rinse and drain the black beans. Heat 1 tablespoon of sunflower oil in a pan, add the minced garlic and ground cumin. Stir for 1 minute, then add the beans, a pinch of salt, and black pepper. Mash with a fork or potato masher into a rustic, creamy purée.

Cut the beef into 4 equal, thin cutlets, then pound them very thin (about 3-4 mm thick). Season both sides with fine salt and ground black pepper.