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. If you don’t happen to like semi-homemade recipes, feel free to try my perfect Blondie Recipe that is from-scratch!

Birthday Blondies

It’s a cake…it’s a cookie…it’s a Birthday Blondie! It is hard to know what name to give this dessert. It’s not a brownie, since it is made with cake mix. And, it’s full of crushed Golden Oreo cookies, which makes it part-cookie. What I do know is that it is a dense, delicious sweet treat that sure is pretty with all of the rainbow sprinkles baked in it! The white chocolate chips also add to the flavor of this dessert that would be perfect for a birthday treat!

OVerhead Image of Birthday Blondies Cut Into Pieces and Pulled Apart

Birthday Blondies Recipe

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!

Ingredients (full recipe below)

  • White cake mix
  • Rainbow sprinkles
  • White chocolate chips
  • Oreo Golden Sandwich Cookies
  • Eggs
  • Vegetable Oil
  • Milk

Raw Ingredients for Birthday Blondies

How to Make Birthday Blondies

This is such a quick and easy treat that could definitely be served in place of a birthday cake. The rainbow sprinkles make it a little extra special for that special day. I think it’s fine to make even if there is not a birthday celebration. All the colors will make you smile.

To make the Birthday Blondies, preheat the oven to 350°F and get out a large bowl. First, combine the cake mix, sprinkles, white chocolate chips, and crushed Oreos in the bowl. Next, add the eggs, vegetable oil, and milk. Blend well. If the mixture is too thick, add a little more milk.

Pour the mixture into a greased 8×8-inch baking dish and bake for 20-22 minutes. They will almost look not quite done and may sink in the middle just a little bit. Chill them in the refrigerator for about 45 minutes before cutting into them. I cut the bars into twelve pieces, but you could definitely make them bigger and cut them into nine bars.

Hand Holding Birthday Blondie with Bite Removed

How to Store the Bars

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.

Looking for More Birthday Treats?

Birthday Cake

Birthday Cake Puppy Chow

Birthday Cake Lasagna

Birthday Cake Cookie Sandwiches

5 from 1 vote

Birthday Blondies

Prep Time 10 mins
Cook Time 22 mins
Chill 45 mins
Total Time 1 hr 17 mins
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 vegetable oil
  • 3 tablespoons milk
  • 1 cup rainbow sprinkles
  • 1 cup white chocolate chips
  • 10 Oreo Golden Sandwich cookies, crushed (with filling)


  • Preheat oven to 350°F.
  • 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 a greased 8x8-inch baking pan.
  • Bake for 20-22 minutes.
  • Let the bars chill in the refrigerator for about 45 minutes before cutting and serving.

Did you make this recipe?

Thank you for making my recipe! You took pictures, right? Well go ahead and post them on Instagram! Be sure to mention me @iambaker and use the hashtag #YouAreBaker.

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!

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