Step 1

Heat broiler. On large rimmed baking sheet, toss tomatillos, garlic, yellow onion, poblano, and jalapeño with oil and 1/2 tsp. each salt and pepper. Turn peppers cut sides down and broil, rotating pan every 5 min., until vegetables are tender and charred, 15 min.

Step 2

Discard skins from poblanos and garlic. Finely chop vegetables and transfer to Dutch oven. Add cumin and coriander and cook on medium, stirring occasionally, 2 min. Add broth, beans, and tomatoes and bring to a simmer; cook 4 min.

Step 3

Meanwhile, toss red onion with lime juice and a pinch each of salt and pepper; let sit at least 10 min. Serve soup topped with pickled onions and cilantro.