Birthday cake blondies are a delicious birthday treat made with a doctored-up yellow cake mix and loads of rainbow sprinkles! It’s a one-bowl recipe made with minimal ingredients and just five minutes of prep time. It’s the perfect sweet treat for all kinds of special occasions!
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Cake Batter Blondies
It’s birthday month in our house and we’re celebrating with all sorts of fun birthday treats and activities (like this birthday scavenger hunt)!
These birthday cake blondies are thick, soft, chewy, and studded with lots of rainbow sprinkles! And because they’re made with yellow cake mix, they’ve got the elements of a traditional birthday cake in every square, without having to make an actual cake.
They’re fun, they’re festive, and are bound to make someone’s day a little brighter!
If you’ve never had blondies – they’re in a league of their own when it comes to baked birthday treats. Typically flavored with brown sugar and vanilla and with a fudgy texture, these are a little more cakey because we’re using a yellow cake mix which eliminates the need for the extra ingredients. No flour, sugar, or leavening agent is needed!
So whether you’re serving up a birthday cake or not, these birthday cake blondies make a great addition to any birthday celebration! And they’re even better with a little birthday cake ice cream on the side!
Why you’ll love this Recipe
- Comes together fast and easy – birthday blondies take just five minutes to prepare and 35 minutes of bake time. It’s waiting for them to cool down before digging in that takes the most effort!
- An anytime treat – with the use of the cake mix, it takes just a handful of ingredients for these cake mix blondies to come together. They’re great for last-minute desserts, for birthday parties as part of a birthday charcuterie board, a school bake sale, or just because you are craving something sweet.
- A one-bowl blondies recipe with cake mix – the entire batter comes together in one large bowl, then it gets transferred to a pan to bake. It’s that easy with minimal cleanup!
Ingredients in birthday cake blondies
Ingredient notes
- Yellow cake mix – use your favorite boxed cake mix brand (Duncan Hines, Betty Crocker, etc), or if you’ve got a homemade cake mix recipe you love, use that! Also, I don’t recommend using anything but yellow cake mix for these – I’ve tried it with white cake mix and funfetti cake mix and it wasn’t nearly as good.
- Vegetable oil – this is replacing the melted butter traditionally found in blondies. The oil will help maintain moisture.
- Rainbow sprinkles – rainbow jimmies are known to bleed less, so I recommend using them. I bought this bulk pack and use it for all sorts of things from my funfetti dip to adding as a topping on rainbow cake balls.
- Milk – I recommend using whole milk for the best results.
How to make Blondies from Cake Mix
These birthday cake blondies are so simple to make – almost as easy as making a basic cake from a cake mix! It’s just making the batter and baking!
Begin by preheating the oven to 350 degrees. Then line a 9×9 baking pan with parchment paper. Or if you don’t have parchment coat the baking pan with nonstick spray.
1 – Make the Blondie Cake Batter
- In the bowl of a stand mixer add in the cake mix, vegetable oil, milk, egg, vanilla extract, and sprinkles. Mix ingredients together until combined and smooth. The batter will be a little firm and that’s totally okay!
- Using a rubber spatula, turn the batter out into the parchment lined baking pan. Spread the batter around evenly into the prepared pan using a rubber or silicone spatula.
2 – Bake the birthday cake blondies
- Place the baking pan into the preheated oven for 30 to 35 minutes, until a toothpick inserted in the center comes out clean. If the toothpick still has some batter on it give it about 3-5 more minutes to bake.
- Let the blondies cool at room temperature for a couple of hours before cutting into them (if you can stand to wait that long).
- Remove the parchment paper from the baking pan and cut the blondies into squares to enjoy!
Note!
While technically you could eat these after they cool to room temperature (which should only take 10-15 minutes), the bars are much easier to cut and will come together better if you wait for 2-3 hours. But I get that it takes patience so if you can’t wait and know that they may fall apart, feel free to eat earlier!
how to store blondies
Store these blondies in an airtight container for up to five days. They do not need to be refrigerated, and I do not recommend refrigerating them so they don’t dry out.
These birthday cake blondies also freeze very well! Wait the full 2-3 hours for them to cool completely before cutting them. Once cut, wrap individual blondies in plastic wrap then place in a freezer safe gallon zipper top bag and freeze for up to three months.
Or if you don’t want to wrap individually, place them carefully into the bag, stacking them with cut pieces of parchment paper in between to keep them from freezing to each other.
When you’re ready to eat these (after being frozen), let them come to room temperature and enjoy.
Tips & tricks
Add mix-ins. peanut butter chips, white chocolate chips, butterscotch chips, cinnamon chips, dark chocolate chips, or milk chocolate chips. You could also drizzle melted white chocolate overtop or add cream cheese or classic cake frosting on top.
Use sprinkles to suit the occasion. This works well with color-themed birthday parties! Again, I recommend using jimmies because the little ball sprinkles (also known as nonpareils) will bleed into the batter.
Recipe FAQs
What is the difference between brownie and blondie?
The main difference between the best blondies and their chocolaty chewy counterpart is that brownies are made with cocoa and blondies are made with vanilla and sweetened with brown sugar. They’re essentially the vanilla version of a chocolate brownie.
How long do these blondies last?
These birthday cake blondies will stay fresh for up to five days at room temperature. Be sure to keep them in an airtight container so they don’t dry out.
Can I use a different cake mix?
I highly recommend using a yellow cake mix for this recipe. I’ve tried it with white cake mix and funfetti cake mix as well and yellow cake mix produces the best results. Normally it’s easy to substitue cake mixes, but I don’t recommend anything but yellow for these birthday cake blondies.
More Birthday Treats
If you’re looking for fun birthday treats, try these other funfetti desserts!
- Funfetti dip – a no-bake, sweet cream cheese dip studded with rainbow nonpareils. Perfect for a crowd.
- Dunkaroo dip – a homemade version of the fun dunkaroo dip packages that come with cookies and frosting. A fluffy dessert dip everyone will love!
- Rainbow cake balls – talk about eating the rainbow! Bite into a white chocolate shell and expose a beautiful array of rainbow-colored cake mix in the middle.
- Fairy bread – soft white bread smeared with real butter and dipped in sprinkles. Can be cut into fun shapes too!
- Funfetti ice cream bread – ice cream and self-rising flour are all you need for the bread. Add some sprinkles for the funfetti look.
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Birthday Cake Blondies
Ingredients
- 1 (15oz) box yellow cake mix
- ¼ cup vegetable oil
- 3 Tbsp whole milk
- 1 large egg
- 1 Tbsp vanilla extract
- ½ cup rainbow sprinkles
Instructions
- Preheat the oven to 350 degrees. Then line a 9×9 baking pan with parchment paper.
- In the bowl of a stand mixer add in the cake mix, vegetable oil, milk, egg, vanilla extract, and sprinkles. Mix ingredients together until combined and smooth.1 (15oz) box yellow cake mix, 1/4 cup vegetable oil, 3 Tbsp whole milk, 1 large egg, 1 Tbsp vanilla extract, 1/2 cup rainbow sprinkles
- Using a rubber spatula, turn the batter out into the parchment lined baking pan. Spread the batter around evenly into the pan.
- Place the baking pan into the preheated oven for 30 to 35 minutes. The cake is done when a toothpick inserted comes out clean.
- When the cake is done baking, let the blondies cool at room temperature for a couple of hours before cutting into it for the best results.
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