Heat the oil in a large Dutch oven over medium heat. Add the diced onion and cook, stirring occasionally, until softened and translucent, about 5 minutes.

Add the minced garlic and grated ginger. Cook for 1 minute until fragrant, stirring constantly so the garlic doesn’t burn.

Stir in the cumin, coriander, turmeric, and cayenne (if using). Cook for 30 seconds, until the spices are fragrant and coat the onion mixture.

Pour in the can of diced tomatoes with their juices. Use your wooden spoon to scrape up any browned bits from the bottom of the pot. Let the tomatoes bubble for 2 minutes, stirring occasionally.

Add the coconut milk and vegetable broth. Stir to combine, then bring the liquid to a gentle simmer.

Add the cubed sweet potatoes and drained chickpeas. Stir in the salt and black pepper. Return the curry to a simmer, then reduce the heat to medium-low. Partially cover the pot and let it cook for 25-30 minutes, stirring gently once or twice, until the sweet potatoes are fork-tender but still hold their shape. The sauce will thicken slightly.

Remove the pot from the heat. Stir in the fresh lime juice. Taste and adjust salt and pepper as needed.

Serve the curry over cooked basmati rice or with warm naan bread. Garnish with fresh cilantro.