Place the sweet potatoes directly on the rack in the oven. Roast until the sweet potatoes are tender, about 1 hour. Let cool completely. When cooled, remove the skin from the potatoes and transfer the flesh to a bowl. Mash with a fork until smooth. Stir in the butter, scallions, sausage and curry paste until combined.
Shape the sweet potato mixture into 3-inch cakes (about 1-inch thick). In a large shallow bowl, whisk the egg until lightly beaten; add the panko to another shallow dish. Dip the potato cakes in the egg, and then coat evenly in the panko.
Heat the oil in a large skillet over medium heat. In batches, cook the fritters in the hot oil until golden, 2 to 3 minutes per side. Transfer to a paper towel-lined plate to drain. Stir together the mayonnaise and sambal; serve the hot fritters with the chili mayonnaise.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.