Preheat the oven to 350 degrees F with a rack in the middle. Grease a 12-inch cast iron skillet or Dutch oven.
In a large bowl, whisk together the starter, yeast, 1/2 cup sugar, salt and vegetable oil. Let the mixture set for 1 minute.
Slowly stir in enough flour to form a soft dough, that is no longer sticky. Turn the dough out onto a floured surface and roll into about a 12x18-inch rectangle and about 1/4- thick.
Evenly pour the butter onto the dough. Sprinkle with sugar and cinamon, to taste.
Beginning at the long side of the rectangle, tightly roll up the dough. Cut the roll into about 8 to 10 1-inch thick pieces.
Place the rolls in the skillet and cover with waxed paper. Let rise in a warm place for 40 minutes, or until nearly doubled in size . Uncover and bake 20 to 25 minutes or until golden brown.
Notes
For high elevation and humidity: add 1 to 2 teaspoons of baking powder.
