Place flour, brown sugar, and softened butter in a bowl and mix well. You may mix by hand or use a pastry tool. Once this is mixed, take out 3/4 cup of this to use as the crumb topping. Set this aside.
The remainder of the mixture is ready to now add beaten egg. Mix well and set aside.
In a one cup measuring cup place the milk and then add the baking soda. Mix well. Now add our secret ingredient -- 2 teaspoons of vinegar or keep adding until the milk mixture bubbles. YOu have just made buttermilk. Yea!
If you have children that want to help, they can make the buttermilk for you and enjoy helping you.
Let the buttermilk sit for 1-2 minutes, but do not let it run over. Now add to the large bowl mixture.
Add the vanilla extract, cinnamon, and mix thoroughly. Now you are ready to bake.
You now have the choice of baking this in 2 greased ceramic pie plates or 1 9X13 greased pan. Pour the mixture into greased pan(s) and sprinkle the topping that you set aside on top of the dough. You may also add a sprinkle of cinnamon on top if you wish. Bake in a pre-heated oven at 375 degrees for 40 minutes or until the cake dough is pulling away from the side of the pan. Test the cake by also placing a toothpick in the center to see if the dough is completely cooked. Let cool for 4 minutes and cut to the desired shape and size. Enjoy!!