This recipe is adapted from Sara Foster's New York Style Crumb Cake. I've halved the recipe and added more spices. Her version is nut free - but we love a little crunch!
Preheat the oven to 325°. Prepare a 8x8 inch square baking pan by spraying with vegetable spray and lining the bottom and sides of a pan with parchment paper. (Cut the paper 8" wide and about 12" long so that the bottom and two sides are covered and there is overhang on either side of the pan). Spray the parchment paper with vegetable spray and set aside.
Make the topping
in a large bowl combine the flour, sugar, cinnamon, nutmeg and allspice and whisk. Make a well in the center of the flour mixture and add the melted butter to it. Mix to combine, then add the pecans and use your clean hands to thoroughly mix them in. Topping should have a loose, crumbly consistency. Set aside.
For the cake
Add the flour sugar, baking powder and salt to a small bowl - and whisk to combine.
In a medium bowl, whisk together the milk, oil, egg and vanilla. Add the flour mixture to the wet ingredients and stir just until combined.
Pour the cake batter into the prepared pan. Add the crumble topping evenly across the batter. (It will look like you've got WAY TOO MUCH topping -- but use it all.)
Bake for 35-40 minutes until the cake rises and the topping bakes into the dough.
Remove from the oven and cool slightly in the pan. Run a knife along the edge to loosen the cake and lift it from the pan to a cutting board. Cut into 9 equal squares. Sprinkle with powdered sugar and serve.