Stir vinegar into milk. Allow to sit for 5-10 minutes. At the same time, in a medium bowl, gently whisk flour, baking powder, and salt together. Set aside.In a separate bowl, cream the butter and sugar together until light and fluffy.
Pour batter into prepared baking pans and bake.Allow bread to cool for 10 minutes in the pan. Then remove it from the pan onto a wire rack to finish cooling.