An old Mark Bittman creation, this salad combines creamy beans, fresh herbs, and both raw and roasted vegetables. A super tart dressing unifies it all—the sweet vegetables and rich beans need it. —Alexandra Stafford
sweet potatoes, peeled and cut into 1-inch cubes, about 4 heaping cups
large red onion, diced to yield about 2 cups
extra-virgin olive oil
Kosher salt and pepper to taste
hot chile, seeded if you are sensitive to heat
limes, juiced to yield about 6 tablespoons
cooked black (or other) beans
bell pepper (any color), seeded and diced, about 1.25 cups
Heat oven to 400° F. Put sweet potatoes on one half of a rimmed sheet pan and toss with 1 tablespoon olive oil. Place onions on other half of pan and toss with another tablespoon of olive oil. Spread vegetables out in a single layer. Season all over with salt and pepper. Roast for 30 minutes, checking after 15 to ensure everything is browning properly. If after the 30 minutes the onions are done, transfer them to a large mixing bowl. Otherwise, return pan to the oven and cook until potatoes begin to brown on corners and are just tender inside. Remove pan from oven.
Put chilies in a blender or mini food processor along with garlic, lime juice, remaining 6 tablespoons of olive oil and a sprinkle of salt and pepper. Process until blended. Mixture will taste super tart. Before you adjust the seasoning, proceed to next step.
Put warm vegetables in a large bowl with beans and bell pepper; toss with dressing and cilantro. Taste and adjust seasoning if necessary. (If mixture is too tart, add olive oil by the tablespoon and sugar by the 1/2 teaspoon—I've found sometimes I need to make adjustments, and sometimes I don't, but I've added as much as 2 extra tablespoons of oil and 1 teaspoon of sugar). Serve warm or at room temperature, or refrigerate for up to a day.