Peel and cut 2 pounds sweet potatoes into large bite-size chunks.
Warm 1 tablespoon olive oil in a large pot, then add 1 onion (chopped) and fry for 5 minutes.Add 3 cloves garlic (grated) and 1 teaspoon ginger (grated), and fry for 1 minute.Add 2 teaspoons curry powder, 1 teaspoon ground cumin, 1½ teaspoon turmeric powder, ½ teaspoon ground coriander, and ⅓ teaspoon red pepper flakes.Toast for 1 minute.
Add 2 cups vegetable broth, 1 can (15 oz) crushed tomatoes, 1 can (15 oz) chickpeas (drained), and the diced sweet potatoes.Season with 1 teaspoon salt and ⅛ teaspoon black pepper, and simmer for 20 minutes.
Add 1 can (14 oz) coconut milk and simmer for 10 minutes until the sweet potatoes are fork-tender and the curry is creamy.Turn the heat off, add 1 teaspoon garam masala and give it a final stir.
Serve sweet potato curry on basmati rice with cilantro, lime, and a dollop of yogurt.
