In a Dutch oven or similar large pot over medium heat, heat the oil until shimmering but not smoking. Once it is hot, add the onion and cook for 4 minutes, until beginning to soften and turn translucent. Reduce the heat as needed so the onion doesn’t turn brown.
Add the garlic and ginger. Sauté just until fragrant, about 30 seconds.
Add the curry powder, garam masala, cumin, turmeric, salt, and cayenne. Stir and cook until the spices are very fragrant, about 1 minute.
Add the potatoes. Stir to coat with the spices.
Stir in the chickpeas, coating them with the spices.
Stir in the tomatoes and coconut milk. Increase the heat to medium high. Once the liquid starts to bubble, reduce the heat to medium and let simmer steadily but gently for 15 minutes, or until the potatoes are tender when pierced with a fork. Stir every few minutes to prevent the curry from sticking.
Stir in the sugar and lemon juice. Then, stir in the peas. Let simmer 1 minute to warm through.
Sprinkle generously with chopped cilantro. Serve hot with prepared rice or naan and an extra sprinkle of cilantro.
Notes
*You can also make this curry with a 14-ounce can of chicken or vegetable broth; it won't be as creamy but will still have nice flavor.
TO STORE: Refrigerate leftover curry in an airtight storage container for up to 4 days.
TO REHEAT: Rewarm leftovers in a Dutch oven on the stovetop over medium-low heat.
I would not recommend freezing this potato curry, as the potatoes can become mealy once thawed.