Preheat oven to 350 degrees and line a 9X13 inch casserole dish with parchment paper and lightly grease the sides of the pan. (I use parchment paper to easily lift my cookie bars out after they have cooled.)
Using a stand mixer, beat butter and sugar for 3 minutes. Scrape down the sides of the bowl as needed.
Add egg, egg yolk, vanilla and almond extract. Mix again. (To get room temperature eggs fast, place eggs in a bowl of warm-hot water for a few minutes.)
In a separate bowl whisk together flour, baking powder, baking soda and salt.
Slowly add in dry ingredients to wet and mix only until combined. Dump into prepared pan and press flat.
Bake for 16-20 minutes. The edges will just barely start to turn golden, then take them out and place the pan on a cooking rack!
FROSTING: Beat butter, vanilla and 2 cups powdered sugar. Continue to add powdered sugar until you like the sweetness level, the frosting should still be soft enough to easily spread on your bars with a knife. If it gets too thick, add 1 or 2 tablespoons of milk!
Once your bars have cooled, lift up on the parchment paper to remove the entire thing from the pan. Frost, immediately add sprinkles (if you wait they won't stick!), and then cut into bars! Enjoy!