Special equipment: 4-inch cast iron pan
Sift the rice flour and salt into a bowl and make a well in the center. Whisk the coconut milk, egg, sugar, ginger, and sesame oil together. Pour the egg mixture into the well in the flour and mix to form a smooth batter. Set the batter aside to rest for 10 minutes before cooking.
In a cast iron pan heat 1/2 teaspoon clarified butter over medium high heat. Ladle 1-ounce of batter into the pan. Cook until edges start to crisp. Flip the Ravadosa to brown the top side. Roll some of the Sweet Potato and Cumin filling in a Ravadosa and tie with a piece of green onion. Repeat with remaining batter.
Cook the sweet potatoes in boiling salted water until just cooked through, about 10 minutes. Drain and set aside in a large bowl. Melt the unsalted butter in a large skillet. Saute the onion until golden, about 5 minutes. Combine the cumin, chilies, garlic, ginger, ground coriander, mustard seeds, and turmeric and stir into the onions and cook for 1 minute. Add the onion mixture to the sweet potatoes and mix well. Stir in the chopped coriander and the lemon juice. Season with the kosher salt.