Preheat oven to 350.
Grease 9x13" baking dish or spray with nonstick spray.
Whisk together flour, sugar, baking soda, baking powder and salt in mixer bowl.
Gradually add in butter while mixing. Mixture will be crumbly.
Add in eggs, vanilla and buttermilk while beating until the mixture is combined (scrape down the bowl periodically).
Set batter aside.
Mix together filling ingredients.
Pour 1/2 the batter into the prepared pan and spread to level.
Sprinkle filling on top of the batter.
Pour remaining batter on top.
Use a butter knife to swirl Through batter.
In a large bowl, whisk together flour, cinnamon, brown sugar, and vanilla.
Cut butter into bowl using pastry cutter or forks until crumbly.
Sprinkle topping evenly over top.
Bake for 45-50 minutes or until the cake sets up.
Allow to cool and dust top with powdered sugar.