How to Make It
Place sweet potatoes in a large pot, and add water to cover by 1 inch. Bring to a boil over medium-high. Add salt, reduce heat to medium, and simmer until tender, 20 to 25 minutes. Drain well. Transfer half of sweet potatoes to a food processor. Add 1 container of yogurt, and process until very airy and whipped; spoon into a large bowl. Repeat with remaining sweet potatoes and remaining container of yogurt. Season with salt to taste.