Peel the sweet potatoes and cook in boiling hot water until tender. Cool in a large baking bowl. Mix the sweet potatoes, yeast, flour and a pinch of salt, add a little water and knead to a soft dough. Let rise in a warm place for about 45 min.
Knead the dough repeatedly with the ball of your hand, divide into 4 parts and form 4 balls. Place each ball in a mold and rise repeatedly for 45 min. Bake in oven heated to 180 °C until bread is lightly browned. Turn and let the other side brown as well.
While still warm, divide diagonally and brush with garlic-parsley butter.