A sweet and savoury vegetarian curry with a fresh light licorice flavour from the tarragon.
Preheat oven to 425F. Line a baking sheet with parchment paper, add the sweet potato and onion wedges, drizzle with 3 tbsp oil, then bake for 25 minutes, stirring halfway though. Remove from oven when onion and potato is soft and beginning to char.
Meanwhile, add the remaining tbsp oil to a large skillet and heat over medium. Add the garlic, cumin, curry powder, and ginger and fry for 30 seconds. Add the lentils, broth, water, salt and nigella seeds and bring to a simmer. Cover and cook for 15 minutes. Remove the lid, stir in the onion and sweet potato and cook uncovered until stew is thickened, about 5 minutes. Remove from heat, stir in the tarragon and the juice from one lime. Serve with rice, yogurt and more lime wedges.