Preheat the oven to 350 degrees, and grease your dutch oven. Set aside.
In a medium bowl, whisk together the cake flour, cinnamon, allspice, nutmeg, baking soda, and salt. Set aside.
In a large bowl, beat together the butter and sugar until fluffy. Beat in the eggs and vanilla until combined. Add in the flour mixture and buttermilk alternating in several additions, starting and ending with the flour mixture. The batter will be thick. Spread evenly in your prepared pan.
In a medium bowl, stir together all the ingredients with a fork. Mash together as needed to get the butter evenly distributed, and to create large crumbs. Sprinkle evenly over the cake batter. Bake for 40-45 minutes, or until a cake tester comes out clean. Enjoy!