Preheat oven to 350 degrees F.
Grease a 8x8 inch square baking pan with baking spray and line with parchment paper. Set aside
In a small bowl, combine sour cream and baking soda. It will double in size
For the streusel, sift together flour, both sugars, spices, and salt. Cut cold butter into small cubes and add to flour mixture. Using a pastry blender, cut butter into flour mixture until it forms a crumble. If you do not have a pastry blender, you can pinch the flour and butter together with your fingers until it forms a crumble. Place in refrigerator until ready to use.
For the cake, sift together flour, baking powder, and salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugar until light and fluffy. Add eggs one at a time and beat well. Add vanilla.
Reduce speed to low and add flour mixture in three additions, alternating with sour cream. Begin and end with flour mixture. Batter will be very thick.
Spoon half of the batter in prepared baking pan and smooth with offset spatula. Lightly tap pan on counter to reduce air bubbles. Sprinkle half of the spiced streusel on top of batter. Cover streusel with remaining batter. Sprinkle with the remainder of the spiced streusel.
Bake for 45-50 minutes until cake is golden, springs back to touch, and toothpick inserted in the center comes out clean. A few crumbs is ok. Start testing for doneness at 45 minutes to prevent overbaking. Remove from oven and allow cake to cool on wire rack for ten minutes. Using the parchment over hang, lift cake from pan and let cool on wire rack for 45 minutes to an hour. Slice into 16 pieces and serve warm or at room temperature.