I’ve got birthdays on the brain this month and next. Husband, dad, sister, an aunt, a few friends, a couple cousins and grandparents were all born in January or February. Not all are still with us, but I always think of them on their special days.
While birthday cake is the traditional celebratory sweet, I like these Rainbow Birthday Cookie Bars as a fun alternative. It’s nice to make something different if you find yourself celebrating lots of birthdays in a short period of time. And these are always a hit with kids.
Bar cookies are my go-to treat when I don’t want to take the time to measure out dough on baking sheets. Make the vanilla-laced batter for these bars, spread in the pan, bake and bingo, you’re done. (There’s a little more work with icing and sprinkle attack.) A cookie for busy days, for sure.
This is an eye-popping recipe because the end result is so colorful. The batter itself, thick and gooey, can be a difficult to spread into an even layer in the pan. I spritz my hands with a non-stick spray and dive in. Clean hands are the best cooking tools. You’ll want the batter as even as you can get it so that the finished bars are all the same depth. That said, if you have to trim off the thinner edges of the cooked bars and nibble while no one is looking, well, that’s the baker’s prerogative, right?
One trick to making bar cookies successfully, especially those that are to be frosted, is to let them completely cool first. This will prevent crumbling. I let the rainbow bars sit for about an hour on a rack before I use the foil or parchment paper liner to lift the entire block from the pan. Then I let them hang out for another hour on the cutting board. You will not be serving them warm. As they cool, the firm.
I cut them first, then frost individually with my handy offset spatula before topping with more sprinkles. I don’t find it that much more time consuming and I like the results better. When I frost before cutting, I get smears that I don’t want. Plus, I can cover up any little mistakes at the edges when I frost this way.
And don’t you want them pretty close to perfect? After all, it is someone’s birthday.
- 1 cup (2 sticks) unsalted butter, melted and slightly cooled
- 1½ cups sugar
- 3 eggs
- 1 tablespoon vanilla extract
- 2 cups flour
- ½ teaspoon salt
- ½ cup rainbow sprinkles, plus more for topping
- 2 cups confectioners’ sugar
- 2 tablespoons unsalted butter, room temperature
- 2 tablespoons milk
- ½ teaspoon vanilla extract
- Prepare a 9- by 13-inch baking pan by lining it with non-stick foil or parchment paper. Leave some hanging over the edges of the pan so that it can be used to lift cooked bars from pan to cutting board. With either foil or parchment, coat generously with non-stick spray just before adding batter.
- Preheat the oven to 350 degrees.
- Melt butter and let it cool for about 15 minutes. Whisk in sugar, eggs and vanilla. Add flour, 1 cup at a time along with the salt. Stir in the rainbow sprinkles until evenly incorporated.
- Spread batter into prepared pan, making an even layer. This will be a thick batter and it might be easier to use your hands after coating them with non-stick spray to spread the dough.
- Bake for 25 minutes, top will be lightly browned. Remove to a wire rack and let cool completely before cutting or frosting.
- Make the frosting while the bars are cooking. In a medium bowl, combine all ingredients and beat on medium until smooth.
- You will have more success with this recipe if the bars are well cooled before cutting them. After the bars have cooled for about 90 minutes, lift the entire block from the pan and move to a cutting board. Either frost the bars before or after they are cut.
- Top liberally with rainbow sprinkles. Store in an airtight container. They keep for about 3 days.