Preheat the oven to 325 degrees.

Line a 9x13 baking pan with parchment paper and grease with non-stick cooking spray.

In a medium bowl, add the dry topping ingredients and stir to combine.

Add the cubed softened butter to the dry ingredients and use a large fork, a pastry blender or just clean hands to mix the butter into the flour creating coarse crumbs. Set aside.

In a large mixing bowl, prepare the cake by adding the butter and sugar. Cream for 3-4 minutes until light and fluffy.

Add the eggs, one at a time, mixing in between.

Add the sour cream and vanilla and mix well. At this point the batter will be very runny and curdled looking. This is normal.

Add the baking soda and salt, then combine.

Add the flour ½ cup at a time, until everything is just combined and there are no more flour streaks. The batter will be very thick.

Spoon the batter into the prepared baking dish and use a spoon or spatula to spread it evenly.

Add the crumb topping evenly over the cake.

Bake for 40-50 minutes or until a toothpick entered into the center of the cake comes out clean.

Allow to cool, then dust with powdered sugar and serve!