Birthday Blondies are easy but delicious dessert cake bars that are full of white cake mix, white chocolate chips, Golden Oreos, and lots of colorful sprinkles. It’s a cake…it’s a cookie…it’s a Birthday Blondie! If you don’t happen to like semi-homemade recipes, feel free to try my perfect Blondie Recipe which is from scratch!

OVerhead Image of Birthday Blondies Cut Into Pieces and Pulled Apart

Ingredients & Substitutions

This dessert is so easy to make and it looks so good that you don’t have to worry about not baking a cake for your birthday! Just whip up these cake bars and celebrate!

Cake Mix: I prefer to use white cake mix for the blondies.

White Chocolate Chips: The white chocolate chips add flavor to the bars that make them perfect for a birthday treat. In fact, I have White Chocolate Blondies you may want to try, too!

Cookies: Look for Oreo Golden Sandwich Cookies.

Sprinkles: Rainbow-colored sprinkles just make me smile. However, you could certainly use sprinkles that were the color of your theme or party.

Raw Ingredients for Birthday Blondies

How to Store Birthday Blondies

These cake bars store well at room temperature or the refrigerator for up to two weeks. Be sure to keep them in a covered container. If you want to freeze them, they will last up to three months in a freezer-safe container. Be sure to label and date the containers and let them thaw overnight in the refrigerator.

Hand Holding Birthday Blondie with Bite Removed
3.50 from 2 votes

Birthday Blondies

Prep Time 10 minutes
Cook Time 22 minutes
Chill 45 minutes
Total Time 1 hour 17 minutes
Birthday Blondies are easy but delicious dessert cake bars that are full of white cake mix, white chocolate chips, Golden Oreos, and lots of colorful sprinkles.


  • 1 box (15.25 ounces) white cake mix
  • 2 large eggs, room temperature
  • ¼ cup (54.5 g) vegetable oil
  • 3 tablespoons milk
  • 1 cup rainbow sprinkles
  • 1 cup (168 g) white chocolate chips
  • 10 Oreo Golden Sandwich cookies, crushed (with filling)


  • Preheat oven to 350°F. Spray a 9×9-inch baking dish with nonstick cooking spray.
  • In a large bowl combine the cake mix, eggs, vegetable oil, and milk and blend well. (Add more milk if the mixture is too thick.)
  • Add the sprinkles, white chocolate chips, and crushed Oreos.
  • Pour the mixture into the greased 8×8-inch baking pan.
  • Bake for 20-22 minutes.
  • Let the bars chill in the refrigerator for about 45 minutes before cutting and serving.


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This recipe was inspired by @hadleyadair on TikTok.

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Meet Amanda Rettke

Amanda Rettke is the creator of I Am Baker, and the bestselling author of Surprise Inside Cakes: Amazing Cakes for Every Occasion – With a Little Something Extra Inside.Over the course of her 15+ year blogging adventure, she has been featured in and collaborated with the Food Network, New York Times, LA Times, Country Living Magazine, People Magazine, Epicurious, Brides, Romantic Homes, life:beautiful, Publishers Weekly, The Daily Mail, Star Tribune, The Globe and Mail, DailyCandy, YumSugar, The Knot, The Kitchn, and Parade, to name a few.

Reader Comments

  1. I have no idea where I went wrong. It’s totally raw after 22 minutes. “Not quite done look” is an understatement in my situation.

    Thoughts on where I went wrong!!?

  2. I had trouble with the cooking time too.
    They were still very raw after 30mins.
    I put them in the fridge overnight to set but still had a raw taste.
    Going to try again in a bigger pan because the edges were delicious!

  3. Amanda, please revisit this recipe and revise it. I made it exactly per the instructions and it yielded WAY more batter than ought to bake in an 8”x8” pan for 22 min. It’s totally raw, and after baking the batter rose considerably. They’re not the adorable thin blondies like the ones pictured. Baking an extra 10min hardly did anything, I’m going on 42 min over here and I’m positive that’s still not enough. 2 stars because these would have been delicious if instructions were to bake in a larger pan. It’s so sad because these are meant to be exciting birthday blondies and I can’t even describe the look of disappointment on the kids’ faces when they didn’t turn out. Birthday bummer. 💔

    1. Hi Monica- I am so sorry there was disappointment on the kids’ faces when these didn’t turn out. I have made these many times and am not sure where the problem lies. You can see by the video that it does work and you can also see that it is a cake-mix recipe, so pretty reliable. 42 minutes in the oven would lead me to believe it is an oven issue, unfortunately.

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