Brown your butter first so it will have time to cool in the fridge.
Add the ½ cup butter to a saucepan and bring to a simmer over medium heat.
Allow the butter to melt then continue stirring until the specks in the butter turn brown. You may notice some foam and that's okay. Once browned, remove from the heat. (Be careful not to let it burn or turn too dark. Place in the fridge while prepping the bars)
Making the Pumpkin Bars
Pre-heat your oven to 350 degrees and line a 10”x15” baking sheet (or jelly roll pan) with parchment paper. I also like to spray a little non-stick spray so everything comes our easily.
In a large bowl, use a hand mixer to combine the oil, applesauce, eggs, sugars, pumpkin and vanilla extract.
In the same bowl, sprinkle in the flour, baking powder, baking soda, salt, cinnamon, and pumpkin pie spice. Start slowly and use the mixer to combine with the wet ingredients until you see no more dry flour. (You can use a spatula to scrape down the sides)
Pour the batter into the lined baking sheet and bake for 30-35 minutes. To check for doneness, insert a toothpick in the center. If it comes out clean, the bars are done.
Cool bars completely either on the counter or the fridge before icing.
Making the Frosting
Add the softened cream cheese, vanilla, and cooled, browned butter to a bowl and mix with the hand mixer until combined.
Add in the powdered sugar and mix slowly until smooth.
Spread the frosting over the cooled pumpkin bars and place in the fridge for about 30 minutes to firm up the frosting.
Cut into squares and store in the fridge for up to 5 days.