Created by Kasey on November 10, 2013
Step 1: Preheat the oven to 350 F.
Step 2: Grease a 9-inch square pan.
Step 3: For the streusel, combine the brown sugar, flour, and cinnamon and stir in the melted butter until evenly combined. Stir in the nuts. Set aside.
Step 4: Cake
Step 5: For the cake, sift the flour, baking powder, salt, baking soda and allspice.
Step 6: In a separate bowl whisk the melted butter, sugar, sour cream, eggs and vanilla. Stir into the flour mixture until evenly blended.
Step 7: Spread half of the batter into the prepared pan and sprinkle half of the streusel on top. Using a knife, swirl the streusel into the batter just a little. Top with the remaining batter, spread and then top the cake with the remaining streusel, giving the cake another little swirl.
Step 8: Bake for 45 to 55 minutes or until a tester inserted in the centre of the cake comes out clean.
Step 9: Cool the cake in the pan to room temperature before slicing.