Combine dry ingredients in a bowl.
Stir in milk followed by oil & egg. Beat on high for 3 minutes.
Add additional flour until dough forms a mass.
On a floured surface, knead 150 turns (about 4-5 minutes).
Cover with plastic or a bowl & let rest 10 minutes.
Meantime, grease an 8-inch round pan and combine the brown sugar and cinnamon in a small bowl.
On a floured surface, roll dough into 12" x 9".
Spread with butter/margarine followed by brown sugar mixture.
Roll up the dough (not too tightly) starting at the 9" end.
Cut 1/2-inch off either end.
With a serrated knife or using dental floss, cut log into 8 even slices and arrange in pan.
Cover with plastic & rise in a warm spot until doubled, 1 - 1 1/2 hours.
Bake in preheated oven at 350° F for about 15 minutes.
Cool in the pan for 10 minutes, then frost.
To make frosting, combine powdered sugar & vanilla and slowly add milk for a spreading consistency.