Preheat oven to 350 degrees F (180 degrees C). Butter and flour an 8x8 inch pan and set aside.
In a large bowl, whisk together melted Unsalted Butter (8 tablespoon), Dark Brown Sugar (3/4 cup), and Granulated Sugar (1/4 cup) until smooth. Add Egg (1) and Clear Vanilla Extract (2 teaspoon) and whisk well.
Add All-Purpose Flour (1 cup), Sprinkles (3 tablespoon), and Salt (1 pinch). Mix together until well combined.
Evenly spread batter in the greased pan and sprinkle the rest of the Sprinkles (1 tablespoon) on top.
Bake for 20-25 minutes. You want the edges to be golden brown and middle to be a little gooey, since it will continue cooking in the hot pan when it is cooling. Then let cool completely, slice and enjoy!