Preheat the oven to 180 degrees.
Mix the Vinegar and Milk and set aside for 10 minutes.
Mix the baking powder,soda and flour together.
Combine all the wet ingredients-Yogurt,oil,vanilla extract, milk with vinegar and the sugar in a bowl.
Take half the flour mixture and mix well with the wet ingredients. Once incorporated add the rest and mix together.
In another small bowl, combine the cinnamon and brown sugar together.
Pour 1/4th the batter in the prepared pan.Sprinkle 1 tsp of Cinnamon Sugar.
Spoon in 1/4th the batter and again sprinkle 1 tsp of Cinnamon Sugar.
Repeat the process till the batter is over.Sprinkle the remaining of the cinnamon sugar on top.
Bake at 180 degree for 20 minutes uncovered.Cover with foil and continue baking for another 10 minutes.Test the cake with a skewer,If it comes out clean(or with crumbs) remove from the oven if not,keep baking for 5-8 minute more.
Cool the cake and serve.