Proof the yeast in 1/2 cup of the lukewarm milk, with 1 teaspoon of the sugar.
When you have a yeast sponge, add the rest of the milk, sugar, and soft butter. Stir in the flour, cup by cup, until you have a dough that you can knead. Work until smooth and shiny, then place in a large buttered bowl, cover with a towel and put in a warm place for about 1 hour or until doubled in bulk.
Take the dough out onto a lightly floured work surface, knead for a few minutes and roll into ropes, about 2" thick. Break off pieces, about the size of an egg, and shape into little round buns.
Place these on buttered baking sheets, cover with a towel and let rise until doubled in bulk, about 45 minutes.
Bake in the oven until they are pale gold, about 15 to 20 minutes.
Cool on a rack.
After they have cooled, use a big fork to slice the top half off each bun. Place both tops and bottoms on a baking sheet; they can be rather close together.
Bake in a 400 degrees oven until light brown, about 10 to 15 minutes. Turn off the heat and let them get crisp.
Let cool completely before eating.
These will keep crisp and fresh for a long time. If they do get soggy, put them back in a low oven and let them crisp again.