Preheat oven to 350°F/175°C. Line a 8x8-inch square pan with parchment paper, leaving an overhang on the sides for lifting the bars out of the pan after baking.
In a small bowl, combine the granulated sugar and ground cinnamon. Set aside.
In a separate bowl, combine flour, pumpkin pie spice, ground cinnamon, cardamom, nutmeg and cloves.
In a large bowl, whisk the melted butter and brown sugar for a minute, until smooth and shiny. Add the egg and whisk until fully combined. Whisk in the pumpkin puree and vanilla until combined and smooth.
Add flour mixture to wet mixture and fold, using a rubber spatula or wooden spoon, just until combined and no flour streak remained. Don’t over mix.
Pour the batter into the prepared baking pan and evenly distribute the batter all the way to the sides of the pan. Sprinkle all of the cinnamon and sugar mixture over the top of the batter.
Bake for 25-28 minutes, until the top is lightly golden and slightly firm to touch, or a toothpick inserted into the center comes out with a few to no moist crumbs attached. The middle will still be undercooked, but they will continue to cook as they cool.
Allow to cool to room temperature on a wire rack, then lift out of the pan and cut into bars (or, for perfectly cut bars, refrigerate for at least 2 hours before cutting). Serve at room temperature.