Preheat oven to 350 degrees F.
Beat eggs, sugar, oil, and pumpkin together in a large bowl. Set aside
In a separate bowl, whisk together flour, cinnamon, nutmeg, cloves, baking powder, baking soda, and salt.
Combine the flour mixture with the pumpkin mixture, until well mixed, but without over mixing.
Coat a jelly roll pan with non-stick spray, and pour batter into it.
Bake at 350 degrees F for 25-30 minutes, until bar is set.
Meanwhile combine all the frosting ingredients together in a large bowl, and mix together with a hand mixer until smooth.
Let pumpkin spice bars cool, then frost, slice, and enjoy!