Preheat the oven to 350, and line an 8x8" pan with parchment paper or foil to prevent sticking.
Combine all of the spices together in a small bowl, and set aside.
Next, whisk together the flour, all of the spices except 1 teaspoon (reserve it on the side for topping after baking), baking powder, and baking soda.
In a separate bowl, whisk together the melted butter, brown sugar, eggs, and vanilla.
Stir the wet ingredients into the dry until no streaks of flour remain.
Pour the batter into the prepared pan, and bake for 25 minutes.
Start testing the bars at 25 minutes--you want them to bake but still be soft in the center. Wet crumbs clinging to the toothpick are okay.
While the bars are still warm, make the topping: Melt the butter. Stir the granulated sugar and reserved spice mixture into the butter and brush on the bars.
Let cool, slice, and serve.
