Preheat oven to 350 °F (175 °C). Line or grease a 9×13-inch baking pan
Make the batter: Cream the softened butter and granulated sugar until smooth. Mix in the pumpkin puree, eggs, vanilla, and heavy cream until fully incorporated.
In a separate bowl, whisk together flour, baking powder, salt, and any optional spices. Add to the wet ingredients, stirring just until no dry streaks remain—avoid overmixing.
Prepare the crumb topping: In another bowl, blend softened butter, brown sugar, flour, and cinnamon until it resembles coarse crumbs.
Assemble: Spread the batter evenly into the pan. Sprinkle the crumb topping all over—avoid packing it down; let it sit loosely.
Bake for about 27–35 minutes, or until a toothpick in the center comes out clean or with a few moist crumbs.
Cool completely in the pan before slicing into bars (this ensures cleaner edges and helps the crumb topping set).
Glaze Step (optional): Once the bars are fully cooled, mix up the maple glaze ingredients until smooth. Drizzle glaze over the top. Allow it to set for 10-15 minutes before slicing so the glaze firms up and slices stay clean.