Preheat oven to 350-degrees. Line a 9x13-inch baking pan with parchment paper or foil, and spray the bottom and sides with baking spray. Set aside.

In the bowl of a stand mixer, affixed with the paddle attachment, add the butter and beat on medium-high speed until light and creamy. Add the brown sugar to the butter and beat until light and fluffy. Scrape down the sides of the bowl as needed. Add the eggs to the mixture one at a time, beating the first egg in completely before adding the second egg. Add the vanilla extract and salt to the mixture and mix on medium-high speed until fully incorporated. Change the mixer speed to low and add the flour and baking powder to the mixture. Mix until barely incorporated.

Remove the bowl from the mixer and use a rubber scraper to ensure all ingredients are incorporated. The batter will be thick. Fold in the Funfetti morsels and sprinkles. Mix until combined. Pour Batter into prepared pan and spread evenly into the pan. Put a little water on your fingers to help evenly spread the batter into the pan. Add additional sprinkles on top to make them look pretty (optional).

Bake blondies in 350-degree oven for 28-minutes. Remove the blondies from the oven and let set and cool completely before slicing into desired sized squares.