Birthday Cake Blondies are my go-to when I want that classic vanilla birthday cake flavor but in a chewy bar that’s easy to slice and serve.
They’re buttery and soft in the middle, with little pops of sprinkles throughout, and that simple vanilla glaze on top makes them taste more like actual cake. I like a tiny bit of almond extract here, but it’s totally optional.
These are especially good for party trays, bake sales, and anytime I want a dessert that looks festive with almost no effort. I usually cut them small because they’re rich, and they hold up really well on a plate.
Why You’ll Love This Recipe
Soft and Chewy: The centers stay tender and chewy, with just enough structure around the edges so they slice cleanly.
Classic Birthday Cake Flavor: Vanilla, brown sugar, sprinkles, and that glaze on top hit the same notes as funfetti cake, just in bar form.
One-Bowl Friendly: After you whisk the dry ingredients together, everything else comes together fast and with minimal cleanup.
Pretty for Parties: Sprinkles in the batter and on the glaze make these look finished even if you’re keeping it simple.
Easy to Adjust: Add white chocolate chips, swap them for chopped white chocolate, or leave them out and keep it all about vanilla and sprinkles.
Ingredients You’ll Need
Blondies
- All-purpose flour: I use regular flour here. Measure it the usual way (spoon and level if you can) so the bars don’t turn dry.
- Baking powder: This gives the blondies a little lift so they don’t bake up too dense.
- Fine salt: Don’t skip it. It keeps the sweetness from tasting flat, especially with the glaze.
- Unsalted butter: Melted butter makes this easy and keeps the texture chewy. Let it cool slightly so it doesn’t scramble the eggs.
- Light brown sugar: This is where a lot of the chewiness comes from. Dark brown sugar works too, just a deeper flavor.
- Granulated sugar: A little white sugar helps the top get that classic shiny blondie look.
- Eggs: Room temperature mixes in more smoothly, but cold eggs will still work if that’s what you have.
- Vanilla extract: Use a vanilla you like the taste of. It’s the main flavor here.
- Almond extract (optional): It gives that “birthday cake” bakery-style flavor. I keep it small because it can take over fast.
- Rainbow sprinkles: I prefer jimmies for baking since they hold their color better. Nonpareils can bleed and look a little muddy.
- White chocolate chips (optional): These add extra sweetness and little creamy bites. You can also use chopped white chocolate, or just leave it out.
Vanilla Glaze (Optional)
- Powdered sugar: This is the base of the glaze. Sift it if it’s lumpy, or just whisk a little longer.
- Milk: Start with less and add as needed. You want a thick drizzle, not something that disappears into the blondies.
- Vanilla extract: A little more vanilla on top really sells the “cake” flavor.
- Salt: Just a pinch makes the glaze taste more balanced and less one-note.
Recipe Instructions
- Preheat the oven: Heat the oven to 350°F. Line an 8-inch square pan with parchment paper, leaving an overhang, then lightly grease the parchment and sides.
- Mix the dry ingredients: Whisk the flour, baking powder, and salt together in a medium bowl, then set aside.
- Mix the butter and sugars: In a large bowl, whisk the melted butter, brown sugar, and granulated sugar until smooth and well combined.
- Add the eggs and extracts: Whisk in the eggs, vanilla extract, and almond extract (if using) until the mixture looks glossy and blended.
- Add the dry ingredients: Fold the flour mixture into the wet ingredients just until you don’t see dry streaks.
- Fold in the mix-ins: Fold in the rainbow sprinkles and white chocolate chips (if using). Stop mixing as soon as everything is evenly combined.
- Spread the batter: Scrape the batter into the prepared pan and spread it into an even layer. Tap the pan on the counter a couple of times to level it.
- Bake: Bake for 22 to 28 minutes, until the edges are set and lightly golden and a toothpick in the center comes out with a few moist crumbs.
- Cool: Let the blondies cool completely in the pan, then use the parchment overhang to lift them out and slice.
- Glaze and finish: Whisk the powdered sugar, milk, vanilla, and salt into a thick, pourable glaze. Drizzle over the cooled blondies, add extra sprinkles right away, then let the glaze set for 10 to 15 minutes before serving.
Some of my tips!
This is the part that really makes a difference. If you only read one section, make it this one because this is where I share the little trick that helps the recipe turn out so well.
Recipe Tips & Tricks
Use jimmies for the sprinkles. They hold their color better in the oven. Nonpareils tend to bleed and you lose that clean “funfetti” look.
Stop mixing once the flour is gone. Overmixing is the easiest way to make blondies turn a little tough. I fold just until the last streak of flour disappears.
Pull them when the center has moist crumbs. If the toothpick comes out totally clean, they’re usually on the dry side after they cool. A few moist crumbs is what you want.
Let them cool completely before glazing. If the bars are even a little warm, the glaze melts and soaks in instead of sitting on top.
Go thicker on the glaze if you want clean drizzles. Start with less milk and add it slowly. It’s easy to thin it out, but hard to fix a runny glaze.
Make some touches!
There are plenty of easy ways to serve this depending on the occasion. Keep it simple, or add a few small touches to make it feel a little more special.
Serving Suggestions
- Milk: A cold glass of milk is classic with these. It’s especially nice if you go heavy on the sprinkles and glaze.
- Coffee or espresso: These are really good with coffee, especially if you like sweet desserts with a bitter drink. I usually do a simple latte or black coffee.
- Ice cream: Serve a blondie square with vanilla ice cream on the side. If you want to lean into the birthday cake thing, add a few extra sprinkles on the ice cream too.
- Fruit: Fresh strawberries or raspberries are nice on the plate. It breaks up the sweetness without making it complicated.
Save it for later
This section covers how to store leftovers and what parts of the recipe you can prepare ahead of time.
Storage and Make Ahead
Store leftovers airtight for up to 4 days. I usually keep them at room temperature if my kitchen is cool; if it’s warm, the fridge is fine (they’ll just be a little firmer).
If you want to make this recipe ahead, bake the blondies and cool them completely, then glaze them the day you plan to serve. The sprinkles on top stay brighter that way.
For longer storage, you can freeze sliced bars up to 2 months. I like to freeze them in a single layer first, then stack with parchment between pieces.
To serve from frozen, thaw in the fridge overnight or let them sit at room temperature until soft. If you want them slightly warm, a short microwave zap works.
A few quick answers
This section covers a few extra details that may help before you head to the recipe card.
Recipe FAQs
What pan size should I use for these blondies?
An 8-inch square pan is what I use for thicker, chewier bars. If you use a larger pan, they’ll bake thinner and faster, so keep an eye on the bake time.
How do I know when blondies are done baking?
Look for set edges that are lightly golden, and a center that doesn’t look wet. A toothpick in the middle should come out with a few moist crumbs, not raw batter.
Can I skip the glaze?
Yes. They’re still very good without it, especially if you add the white chocolate chips. If you want a simple finish without glaze, a light dusting of powdered sugar works too.
Why did my sprinkles bleed into the batter?
This usually happens with nonpareils or very soft “natural dye” sprinkles. I get the most reliable results with the classic jimmies-style sprinkles.
Can I use only vanilla and leave out the almond extract?
Absolutely. The almond extract just gives a little extra “birthday cake” flavor, but the blondies still taste like vanilla funfetti without it.
You might also like
Before you go, take a look at a few other recipes below the recipe card. They use similar ingredients in a different way and are worth saving too.
MORE DINNER RECIPES TO TRY
Birthday Cake Blondies
INGREDIENTS
Blondies
- 1 1/2 cups all-purpose flour
- 1 tsp baking powder
- 1/2 tsp fine salt
- 1/2 cup unsalted butter melted and slightly cooled
- 1 cup light brown sugar packed
- 1/4 cup granulated sugar
- 2 large eggs room temperature
- 2 tsp vanilla extract
- 1/4 tsp almond extract optional
- 1/2 cup rainbow sprinkles plus more for topping
- 1/2 cup white chocolate chips optional.
Vanilla Glaze Optional
- 1 cup powdered sugar
- 2 to 3 tbsp milk
- 1 tsp vanilla extract
- pinch of salt.
INSTRUCTIONS
Prep and Batter
- Heat oven to 350 F and line an 8 inch square pan with parchment leaving overhang then lightly grease
- whisk flour baking powder and salt in a bowl
- whisk melted butter brown sugar and granulated sugar until smooth then whisk in eggs vanilla and optional almond extract
- fold dry ingredients into wet just until no dry streaks remain then fold in sprinkles and optional white chips.
Bake and Finish
- Spread batter evenly in pan and tap pan to level
- bake until edges are set and lightly golden and a toothpick inserted in the center comes out with a few moist crumbs 22 to 28 minutes
- cool completely in pan then lift out and slice
- whisk glaze ingredients to a thick pourable consistency drizzle over cooled blondies and immediately add extra sprinkles then set 10 to 15 minutes before serving.
