Choose dried chiles that are fairly flexible, a sign they’re not too old.
- 2 tablespoons raw shelled pumpkin seeds (pepitas)
- 1 large dried pasilla or ancho chile, stemmed, seeds removed
- 1 tablespoon vegetable oil
- 1 medium onion, coarsely chopped
- 4 garlic cloves, peeled, crushed
- 1 14.5-oz. can fire-roasted or plain diced tomatoes
- 4 cups low-sodium chicken broth
- 2 14.5-oz. cans black beans, drained
- ½ cup crumbled queso fresco or feta
- Lime wedges (for serving)
Preheat broiler. Broil poblano chiles on a foil-lined baking sheet, turning occasionally, until blackened, 8–10 minutes. Transfer to a bowl, cover with plastic wrap, and let steam 15 minutes. Peel, seed, and finely chop.
Meanwhile, toast seeds in a small dry skillet over medium-high heat, tossing occasionally, until golden, about 5 minutes; transfer to a plate. Toast pasilla chile in same skillet until slightly darkened and pliable, about 1 minute; transfer to plate.
Heat oil in a medium saucepan over medium-high heat. Add onion and garlic and cook, stirring occasionally, until onion is soft and golden brown, 8–10 minutes. Transfer to a blender, add tomatoes and pasilla chile, and blend until smooth.
Return tomato mixture to saucepan and cook over medium-high heat, stirring often, until thick, 6–8 minutes. Stir in broth; season with salt. Bring to a boil, reduce heat, and simmer until soup is slightly thickened, 10–15 minutes. Stir in black beans and poblano chiles. Cook, stirring occasionally, until warmed through, about 5 minutes.
Serve soup topped with queso fresco and pumpkin seeds, with lime wedges alongside.
DO AHEAD: Soup can be made 2 days ahead. Cover and chill.