Many pumpkin desserts are dense and heavy, but these bars are light and more cake-light, with a lovely cream-cheese swirl. For a fancier presentation, serve it with a dollop of whipped cream sprinkled with cinnamon.
Prepare pan - either a 10x15 jelly roll (for bars) or a 9x13 (for cake). I like to line my pans with parchment paper.
Combine flour, spice, baking powder and soda in a bowl. Set aside.
In a mixer, combine sugar, brown sugar and softened butter. Add pumpkin, and then eggs and whites. Add flour mixture; mix well. Spread into prepared pan.
Make cream cheese topping: blend cheese, 3 T. sugar and milk until smooth. Drizzle across top of batter; then use a knife to zigzag through the batter and filling, creating a nice design.
Bake according to your pan size: 10x15 pan 25-30 minutes, 9x13 pan 35 minutes. Test with a knife (better than a toothpick test) to make sure the bars are completely done and not under-baked. I watch for the cake to puff up all over, even creating little cracks on the top, as an indicator that it is thoroughly baked. Under-baked bars get gummy.