Make this colorful main course a day ahead to give flavors a chance to meld.
- 2 tsp. olive oil
- 1 medium-sized onion, finely chopped (about 1 ½ cups)
- 2 Tbs. curry powder
- 2 medium-sized sweet potatoes, peeled and cut into 1-inch chunks (about 1 ½ lb.)
- 1 head cauliflower, stemmed and separated into florets (about 2 ½ lb.)
- 1 cup brown lentils, rinsed
- 2 14.5-oz. cans low-sodium diced tomatoes with juice