Beat sugar, salt and egg together. Add vanilla and fat, and cream into sugar. In a separate bowl, combine flour, soda and buttermilk. Stir two mixtures together. Place on floured surface and flatten to 1 cm. Cut into 10 cm rounds and cut out 3 cm centers. Drop into hot oil in a skillet, and brown on each side. Drain on paper towels. Coat warm donuts with powdered sugar, if desired. Makes 1 batch.