Put a skillet on medium heat and add the ghee or butter. (Ghee, which is traditional in Indian cooking, is just butter with the milk solids removed, and it can withstand higher temperatures than butter without burning.)

Once the butter is hot, add the cumin seeds and let them sizzle for 5 seconds before adding the diced onion. Let the onion cook for 2 minutes, stirring occasionally.

In a small bowl, mix the garlic, ginger, turmeric, coriander, cayenne powder, salt, and 1 tablespoon of water.

Add the spices to the onion mixture and mix, cooking for another 2 minutes. It will smell strongly aromatic. This step is important because the spices become toasted and release their flavor.

Next, add the potatoes. Stir to coat them with the onions and spices. Add about a cup of water and cover the pan with a lid. Let it cook for about 10 minutes, checking occasionally to stir and make sure nothing is burning. Add more water as needed. You want the final mixture to be only a bit moist, but the water helps everything cook evenly.

Test the potatoes with a fork: if you can easily pierce them, they’re ready. Once they are, add the kale and stir until the kale is wilted. Taste and add more salt if needed.

To assemble the rolls, scoop 1/8 of the mixture into the center of a roti, distributing it in an even line. Roll it up.

Serve two roti per person with cilantro and a generous dollop of raita, either over the top or on the side.