1. Preheat Oven 350 degrees F.

For the Crumb Topping:

1. In a medium sized bowl combine the brown sugar and the granulated sugar, salt, and the cinnamon.
2. Add the melted butter and stir until well combined.
3. Fold in the flour until it is fully combined and set the mixture aside while preparing the cake.

For the Cake:

1. In a large bowl, sift together the flour, baking powder, baking soda and the salt.
2. In a separate bowl using an electric mixer, cream the butter until it is smooth; then add the sugar continue to mix to a light, smooth consistency.
3. Add the eggs, one at a time, while mixing.
4. Add the sour cream and vanilla and continue to mix.
5. Slowly add the dry ingredients while mixing.
6. Butter a 9 x 13-inch glass baking pan.
7. Place the batter in the prepared pan.
8. Take a handful of the topping mixture and make a fist. Break off chunks of the topping and place them over the cake. Repeat this process using up all the topping.
9. Bake 45 – 50 minutes or until the toothpick test comes out clean.