In a large bowl, dissolve the yeast in warm water. Add the oil and sugar, and let the mixture stand for five minutes.
Add the egg, the salt and enough flour to form a soft dough.
Turn the dough onto a floured surface. Knead the dough until it is smooth and elastic, three to five minutes. Do not let it rise.
Divide the dough into 12 pieces. Shape each piece into a ball and place them 3 inches apart on greased baking sheets.
Preheat the oven to 425°. Cover the dough balls on the baking sheet and let them rest for 10 minutes. Then, bake the buns until golden brown, 8 to 12 minutes.
If desired, brush the buns with butter and sprinkle them with sesame seeds. Move the buns from the baking sheet to wire racks to cool.
