The fudgiest chocolate brownies with a confetti cookie layer – what could be better than that? Oh I know, how about then stuffing it with birthday cake oreos? These oreo birthday cake brownies with rainbow sprinkles are now a household favorite, we couldn’t stop eating them. What makes them even sweeter is there’s only 25 minutes of prep time!
Tell me about this recipe!
- This is my absolute favorite fudgy brownie recipe. These brownies are so fudgy due to the extra egg yolk and a lot of butter. I use a combination of melted chocolate and dutch process cocoa to make them extra chocolatey.
- The best brownies for me always have a crinkle, crackly top! I’ve tried a few methods to get this top, and the best one for me is whisking the sugar and eggs together for about 8 minutes, until it has become much lighter in color.
- The bottom layer is a confetti cake batter blondie mix. Unlike most of my blondie recipes, it has some baking powder in it to give it a more cake like texture. It’s then folded with some rainbow sprinkles!
- The two layers are then stuffed with birthday cake oreos! You can definitely use just regular oreos though, to be honest there isn’t a huge difference in the taste.
Ingredients Needed
The printable recipe card with the full list of ingredients and instructions can be found at the bottom of this post.
Ingredient Notes
- Cocoa Powder: I recommend using dutch-process cocoa powder in this recipe. It will give you a much darker and richer flavor.
- Butter: I always use European style butter, like Kerry Gold, in all of my recipes. This will make your finished bakes so much richer and creamier, due to the higher butterfat content.
- Oil: You’ll need to use a neutral oil in the brownies. This could be vegetable oil, canola oil, or rapeseed oil.
- Sprinkles: You should be using long stranded sprinkles, also known as jimmies, for the cake batter layer. If you used nonpareils (the small circular balls) they might bleed in the batter and you won’t see them as well.
How to make this recipe
One 
Two
One: Start off by making the birthday cake layer. Melt the butter in a small saucepan.
Two: In a jug, whisk together the sugars, egg, vanilla and salt until smooth.
Three 
Four
Three: Pour in your melted butter and whisk again until nice and smooth.
Four: Whisk in your flour and baking powder, but do not overmix.
Five 
Six
Five: Fold in your sprinkles, but keep about 2 tablespoon to the side (you’ll add those to the top of your brownies when they’re finished baking!).
Six: Line an 8×8 pan with foil. Pour the batter into the bottom and use a small offset spatula to make the layer even. Set to the side.
Seven 
Eight
Seven: Melt your butter and chocolate together. You can either do this in the microwave in short bursts, or in a double boiler, or in a small saucepan. Keep a close eye on it so the chocolate doesn’t burn! Take it off of the heat.
Eight: Add in your cocoa powder and whisk until smooth.
Nine 
Ten
Nine: In a large bowl, add in your eggs, egg yolk, sugars, oil, and vanilla.
Ten: Use a hand held mixer to whisk everything together for about 6-8 minutes. It should become very light in colour with bubbles. This is what will give us a crackly crust on top of the brownies.
Eleven 
Twelve
Eleven: Whisk your flour and salt together.
Twelve: Pour the melted chocolate mixture into the sugar mixture and mix together until smooth. Finally, add in your flour mixture and fold until there are no more air pockets.
Thirteen 
Fourteen
Thirteen: Place your oreos on top of the birthday cake layer.
Fourteen: Pour the brownie batter on top. Bake at 350 degrees for 45-50 minutes. The top should have a very thin layer and the middle might still be a little bit jiggly. Take it out of the oven and add your extra sprinkles on top. Let cool completely.
Recipes Tips:
- The secret to getting a thin and crackly crust is all in mixing the sugar and eggs together. Whisking them together until they’re properly aerated is going to give us a paper crust to the brownies.
- Make sure to keep an eye on these brownies when they’re in the oven. You do not want an overbaked brownies!
- I highly recommend using a weighing scale and measuring out your ingredients the metric way. It makes a huge difference to your baking and is the most accurate way to bake!
- Let the brownies cool until you lift them out of the pan. If you do it while they’re still too hot or warm, they will collapse when you try to take them out.
- Using a lighter metal baking pan will mean your brownies won’t get too hard on the bottom or on the sides.
Frequently Asked Questions
Yes! You can double all of the ingredients and bake it in a 9×13 inch baking pan.
You could leave out the oreos completely, or use a different oreo variation (double stuff, peanut butter, mint, so many choices!). You could swirl the top of the brownies with peanut butter which would be delicious. If you don’t have dutch process cocoa powder, you can use regular cocoa powder.
You can store them in an airtight container for up to 4 days in the fridge. I love keeping my brownies in the fridge as I think it makes them more fudgy!
Other Bar recipes to try:
Make sure to tag me on Instagram @alpineella and leave a review below if you’ve made these brownies! If you want more baking ideas, you can follow me on Pinterest
Birthday Cake Brownies
Equipment
- 8×8 pan
Ingredients
Brownies
- 2 eggs room temperature
- 1 egg yolk room temperature
- ¾ teaspoon vanilla extract
- 5½ ounces unsalted butter
- ¼ cup cocoa powder dutch process
- ½ cup all purpose flour
- 4 ounces dark chocolate chopped
- 1 teaspoon kosher salt
- ½ cup light brown sugar
- ½ cup granulated sugar
- ¼ cup vegetable oil
Funfetti Layer
- 9 oreos
- 1 egg room temperature
- ½ tablespoon vanilla extract
- ½ cup light brown sugar
- ¼ cup granulated sugar
- 1 ⅛ cup all purpose flour
- 6 tablespoon unsalted butter
- ¼ teaspoon baking powder
- ½ cup sprinkles
- ½ teaspoon kosher salt
Instructions
Make Funfetti Layer
- Preheat oven to 350°F/175°C. Line an 8×8 pan with foil and set aside.
- In a small saucepan melt your butter.
- In a large jug, whisk together the sugars, vanilla, and salt. Add the egg and whisk until smooth.
- Pour the butter into the jug and whisk.
- Pour in the flour and baking powder, whisk until there are no more pockets of flour but don't overmix.
- Fold in your sprinkles.
- Pour the batter into the bottom of your pan. Place your oreos on top.
Brownies
- In a small bowl, whisk together the flour and salt.
- In a large bowl, place your eggs, egg yolks, sugar, oil and vanilla extract. Mix together using a hand held mixer for about 6-8 minutes until well mixed. This is what will give you a thin crust on top!
- Place a small saucepan with about an inch of water over medium/low heat until it begins to simmer. Place a heat proof bowl over it and melt your butter and chocolate together until smooth. Take off the heat.
- Add in your cocoa powder to the butter and whisk until smooth.
- Pour this chocolate mixture into your sugar mixture and whisk until smooth.
- Fold in your flour mixture and mix until there are no more flour pockets.
- Pour the brownie batter on top of the funfetti oreo layer. Bake for 45-50 minutes. The top should have crackled and a toothpick inserted will come out with a few crumbs. While still warm, you can sprinkles over extra sprinkles on top!
- Let cool for several hours until you slice it into bars.
Chere
Question about butter please!
Funfetti ingredients ask for tbsps of butter. Got it!
Brownie ingredients ask for 5.5 oz of butter = which would be 11 tbsp of butter…seems like a lot of butter for the brownies.
Just checking – is oz right? or should it be tbsp?
chere
The funfetti layer calls for salt in the instructions but salt is not listed in the ingredients for funfetti.
“Make Funfetti Layer
Preheat oven to 350°F/175°C. Line an 8×8 pan with foil and set aside.
In a small saucepan melt your butter.
In a large jug, whisk together the sugars, vanilla, and salt. Add the egg and whisk until smooth.”
How much salt? Does it use some of the 1tsp salt from Brownie items?
Ella
Hi there! So sorry about that, for some reason it got missed off the ingredients list! For the funfetti layer it is 1/2 tsp of kosher salt. I’ll pop that into the recipe card! Then for your other comment about the butter, that is correct – these brownies do have a lot of butter in them!
Chere
Thanks so much for your fast answers! I cannot wait to see the faces when the kids find the Oreo surprise inside!
Will Gilbert
These are amazing. Love the crackly top and Oreo treat inside!