Combine flour,baking powder,salt and baking soda in a medium bowl and mix well.Stir in vegetable oil.Add buttermilk and stir just until blended.
Knead the dough on a lightly floured surface until smooth.Roll dough into a 15x8-inch rectangle.
Preheat the oven to 400.Grease a 9-inch round baking pan lightly.
Spread butter over the dough.Combine granulated sugar and cinnamon in a small bowl and mix well.Sprinkle over butter.Roll up rectangle,jelly roll fashion,starting from one long side.Pinch seam to seal.
Cut the roll into 1 1/2 inch slices.Arrange the slices,cut side up,in prepared baking pan.Bake until lightly browned,about 15 to 20 minutes.Remove from oven.Pour milk over the top,if desired.Serve hot.