Preheat the oven to 350°F. Lightly spray an 8x8 inch baking pan with cooking spray and set aside.
In a medium bowl, mix together the flour, salt, baking powder and baking soda.
In the bowl of a stand mixer, cream together the unsalted butter and 1 cup granulated sugar until light and creamy. Add in the eggs one at a time, mixing until fully combined. Mix in the vanilla and sour cream.
Slowly mix in the dry ingredients into the wet ingredients until just combined. Do not overmix.
In a small bowl, mix together the crumb ingredients until the pecans are fully coated.
Spread half of the cake batter in the prepared pan. Spread half of the crumb mixture, then top with remaining half of the cake batter and crumb mixture.
Bake in the preheated oven for 35-40 minutes, or until a toothpick inserted comes out clean. Allow to cool slightly before cutting into slices.