- 1 ounce dried pasilla (negro) chiles (about 6 medium)
- 3 tablespoons extra-virgin olive oil, divided
- 1 medium onion, sliced ¼-inch thick
- 4 cloves garlic, finely chopped
- ½ cup Mexican crema (see Tip) or crème fraîche
- ¼ cup water
- ½ teaspoon salt, divided
- 1 teaspoon red-wine vinegar
- 1 pound long beans or green beans, trimmed
- 1Remove stems, seeds and membranes from chiles. Heat a medium skillet over medium-high heat. Add the chiles and toast, turning with tongs and pressing down on them frequently, until very fragrant, 2 to 3 minutes. Transfer to a bowl and add enough cold water to cover. Place a plate on top of the chiles to keep them submerged and soak until very soft, 30 to 45 minutes. Drain and cut into ¼-inch-wide strips.
- 2Preheat grill to medium. (If using green beans, place a grill basket on the grill while it preheats.)
- 3Meanwhile, heat 1 tablespoon oil in the pan over medium heat. Add onion and cook, stirring occasionally, until very soft and golden brown, about 8 minutes. Add garlic and cook, stirring, for 1 minute. Remove from heat.
- 4Using a slotted spoon, transfer half of the onion mixture to a mini food processor. Transfer the other half to a small bowl, leaving as much oil as possible in the pan. Add 1 tablespoon oil to the pan and return to medium heat. Add the chile strips and cook, stirring constantly, until the chiles are aromatic and have changed color, about 1 minute.
- 5Add half the chiles to the food processor along with crema (or crème fraîche), water and ¼ teaspoon salt. Blend until smooth, 1 to 2 minutes. Scrape the sauce back into the pan. Cover and place over low heat to keep warm.
- 6Add the remaining chiles to the onion mixture in the bowl. Stir in vinegar and ⅛ teaspoon salt.
- 7Toss beans with the remaining 1 tablespoon oil and ⅛ teaspoon salt. Grill, turning often, until tender-crisp, about 6 minutes. Serve the beans with the sauce and the chile-onion mixture.
- Tip: Mexican crema is a tangy-sweet cultured cream with a taste and texture in between sour cream and crème fraîche. It’s increasingly available at well-stocked supermarkets, or find it at Latin markets.