Combine the butter, sugar, salt and warm water. Sprinkle the yeast over top. Add the flour and mix until it forms a dough. Knead for 4 minutes until dough is smooth. Transfer the dough to a bowl, cover and let rise for 1 hour. Shape into 4 equal balls, place on a lined baking sheet, cover with towel and let rise another 30 minutes.
Boil dough balls in water and baking soda for 1 minute.