Preheat the oven to 350 degrees F. Line a 10”x15” pan with parchment paper, then coat the pan with cooking spray.
Place the flour, sugar, brown sugar, pumpkin pie spice, salt, baking soda and baking powder in a large bowl. Stir to combine.
Add the vanilla extract, eggs, vegetable oil and pumpkin puree to the bowl. Stir until just combined.
Spread the batter evenly into the pan.
Bake for 25 minutes or until set and lightly browned. Cool completely in the pan.
Place the butter and cream cheese in the bowl of a mixer and mix until light and fluffy, about 2-3 minutes.
Add the powdered sugar, one cup at a time and mix on low speed until combined. Add the vanilla extract and mix for 30 seconds.
If the frosting is too thick, add 1 teaspoon of milk at a time until desired consistency is reached.
Spread the frosting evenly over the pumpkin bars. Top with sprinkles. Cut into squares and serve, or store in the refrigerator until you’re ready to eat.