Roast the sweet potatoes and onions early and let the salad chill until serving time. If the potatoes soak up all the dressing, add a bit more olive oil and lime juice just before eating.
4 medium sweet potatoes, peeled and cut into 1-in. chunks
2 medium onions, peeled and cut into 1-in. chunks
1/4 cup olive oil, divided
1 tbsp Mexican chili powder
1 1/2 tsp ground cumin
1 tsp salt
1 540-mL can black beans, drained and rinsed
1/4 cup lime juice
2 tbsp chopped cilantro, or parsley (whichever you prefer)
Preheat the oven to 400°F (200°C). Spray a large baking pan or cookie sheet with non-stick baking spray.
In a large bowl, toss the sweet potatoes and onions with half of the olive oil (just half!), the chili powder, cumin and salt. Spread out on the prepared baking pan and place in the oven. Bake for 30 to 40 minutes, stirring once or twice, until tender but still firm.
Remove from the oven and dump back into the large mixing bowl. Add the black beans and lime juice, and toss gently to mix (but don’t mash up the beans or potatoes). Let cool to room temperature.
Add the cilantro or parsley, drizzle with the remaining olive oil and toss to mix. Serve chilled or at room temperature.