12tablespoons(170g)1 1/2 sticks, salted butter, melted and cooled slightly so it isn't piping hot (but don't let it solidify)
1cup(212g)granulated sugar
½cup(106g)light brown sugar
2large eggs
1tablespoonclear vanilla extract (see note)
2cups(284g)all-purpose flour
½cup(57g)dry milk powder
1teaspoonbaking soda
½teaspoonsalt
½ to ¾cup(85 to 142g)rainbow sprinkles (see note)
Instructions
Preheat the oven to 350 degrees F. Lightly grease a 9X13-inch aluminum baking pan and set aside (I haven't made these bars in a glass pan; if doing so, you might reduce the oven temp to 325 degrees).
In a large bowl using a handheld electric mixer or in the bowl of a stand mixer fitted with the paddle attachment, mix the melted butter, granulated sugar and brown sugar together until well-combined. Add the eggs and vanilla and mix until lightly and creamy, 2-3 minutes.
In a medium bowl, whisk together the flour, milk powder, baking soda, salt and sprinkles.
Add the dry ingredients to the batter and stir with a wooden spoon or spatula until just combined and no dry streaks remain. Mixing with the electric mixer may break apart the sprinkles.
Spread the batter evenly in the prepared pan and bake for 20-25 minutes until the edges pull away from the sides of the pan and they are lightly golden (the edges may rise slightly higher than the center, especially as they cool - that's ok; there's an edge-lover in just about every family or group of friends). Don't overbake! Let cool completely before cutting into squares. These keep very well for several days covered at room temperature (or chilled - yum!).
Notes
Vanilla Extract: so I know clear vanilla extract may not be the most common pantry item but it helps these bars stay a bit lighter in color since the brown sugar darkens the batter a bit. If you don't have clear vanilla extract, use 1/2 to 1 teaspoon pure vanilla extract instead.Rainbow Sprinkles: for the rainbow sprinkles, I use sprinkles like these; you can find smaller containers of similar sprinkles at craft/cake decorating supply stores and many grocery stores - just make sure you have enough for the recipe. Sprinkle Colors: you can use particular colors of sprinkles (the blue and green ones tend to "muddy up" the bars a little but we didn't mind although I'd strongly suggest avoiding black and brown sprinkles); no matter the color, be sure to use the long skinny sprinkles (not the tiny little sprinkles called nonpareils).