Birthday cake blondies are soft, chewy bars studded with white chocolate and rainbow sprinkles. This easy one‑bowl blondie recipe is made from scratch (no cake mix) and comes together quickly for a nostalgic, birthday‑cake‑style treat.
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I’ve been baking blondies for years because they’re fast, forgiving, and endlessly adaptable. I rotate simple blondie variations at home — from strawberry to brown butter to raspberry — because a tray of chewy blondies is the perfect easy dessert when time is tight.
This version captures that birthday‑cake feeling using white chocolate, colorful sprinkles, and a little almond extract for depth. The batter is mixed in one bowl, baked in an 8×8 pan, and yields tender, fudgy bars with melty white chocolate pockets and bursts of sprinkle color.
💗 Why you will love these rainbow sprinkle blondies
Nostalgic — white chocolate and sprinkles bring birthday memories to every bite.
Easy — made in one bowl with melted butter for minimal cleanup.
Simple ingredients — no cake mix required; pantry‑friendly staples are all you need.
Texture — chewy, fudgy blondies with melty white chocolate and soft centers.
💭 What are blondies?
Blondies are a rich, buttery, vanilla‑forward cousin to brownies. They are meant to be soft and chewy with a dense, fudgy crumb rather than a cakey texture.
🛒 Ingredients and substitutions
Scroll to the recipe card below for exact measurements and printable directions.
- Butter — melted unsalted butter for richness. If using salted butter, omit or reduce added salt.
- Sugar — a mix of granulated and brown sugar gives sweetness and chew; dark or light brown sugar works.
- Eggs — bind and enrich; use large eggs at room temperature.
- Kosher salt — balances sweetness; halve the amount if using table salt.
- Vanilla and almond extract — vanilla for warmth, a touch of almond for classic birthday‑cake flavor. Omit almond if you prefer.
- All‑purpose flour — provides structure. For gluten‑free, use a one‑to‑one gluten‑free flour replacement.
- White chocolate — chopped baking bar or chips; gives melty pockets. Milk or dark chocolate can substitute.
- Sprinkles — jimmies or larger nonbleeding sprinkles are best; avoid tiny nonpareils that can bleed color.
Pro tip — to quickly bring eggs to room temperature, place them in warm tap water for 5–10 minutes.
🥣 How to make one‑bowl blondies
Preheat the oven to 350°F and line an 8×8 baking pan with parchment paper.
Whisk melted butter with granulated and brown sugar plus salt until combined.
Add the eggs, vanilla, and almond extract. Whisk until the mixture is smooth and glossy, about one minute.
Fold in the flour with a spatula until most flour is incorporated but a few streaks remain. Gently fold in chopped white chocolate (or chips) and sprinkles.
Spread the thick batter into the prepared pan and smooth the top. Add a few extra white chocolate pieces and sprinkles if you like.
Bake 25–35 minutes, until edges are lightly browned and a tester in the center comes out with a few moist crumbs. Avoid baking until the tester is completely clean — that indicates overbaking.
Cool the pan on a wire rack, then lift the bars from the pan using the parchment and cut into squares.
💬 Frequently asked questions
Do I have to use almond extract?
No. Almond extract enhances the birthday‑cake flavor, but you can replace it with extra vanilla if you prefer. Note: if you have nut allergies, check product labels before using almond extract.
Can I double the recipe?
Yes. Double the ingredients and bake in a 9×13 pan. Baking time should be similar, but check for doneness with a tester in the center.
👩🏻🍳 Tips for the best birthday cake blondies
- Measure ingredients accurately — a kitchen scale gives the most consistent results.
- Avoid overmixing once you add the flour to keep the bars tender and fudgy.
- Do not overbake; the bars will continue to set as they cool.
- Use a light‑colored metal 8×8 pan for even baking. If using glass, reduce oven temperature by 25°F and expect longer bake time.
- If you need to speed cooling, once the pan is cool enough to handle, place it in the refrigerator.
🫙 How to store
Store blondies in an airtight container at room temperature for 3–4 days. They also freeze well for up to three months; thaw before serving.
If you make these blondies, please share a photo and tag @twosugarbugs on Instagram — it always makes my day!
🤍 More blondie bar recipes
- Blueberry Blondies
- Peanut Butter Blondies
- One Bowl Biscoff Blondies
If you try this recipe, please come back and leave a review and a star rating — I read every comment and love hearing from you!
📖 Recipe
One Bowl Birthday Cake Blondies
Soft, chewy blondies filled with white chocolate and rainbow sprinkles. Made without cake mix and mixed in one bowl.
For best results, use weight (metric) measurements when available.
5 minutes
30 minutes
35 minutes
Ingredients
- ¾ cup unsalted butter, melted (170g)
- ¾ cup granulated sugar (150g)
- ¾ cup packed brown sugar (150g)
- ½ teaspoon kosher salt
- 2 large eggs, room temperature
- 2 teaspoons vanilla extract*
- ½ teaspoon pure almond extract**
- 1 ¾ cup all-purpose flour (219g)
- 4 ounces white chocolate, chopped (114g) or ⅔ cup white chocolate chips (114g)
- ½ cup sprinkles (80g)
Instructions
- Preheat oven to 350°F (177°C) and line an 8×8 baking pan with parchment paper.
- In a medium to large bowl, whisk together melted butter, granulated sugar, brown sugar, and kosher salt until combined.
- Add the eggs, vanilla, and almond extract. Whisk until smooth, scraping the bowl as needed, about 1 minute.
- Fold in the all‑purpose flour with a spatula until most flour is incorporated but a few streaks remain. Gently fold in the white chocolate and sprinkles.
- Spread the thick batter into the prepared pan and smooth the top. Top with extra white chocolate or sprinkles if desired.
- Bake 25–35 minutes, until edges are lightly browned and a tester in the center comes out with a few moist crumbs. Cool in the pan on a wire rack.
- Lift the bars from the pan using the parchment and cut into desired sizes.
Notes
*Imitation vanilla works well for that birthday‑cake note; pure vanilla is fine too.
**If you skip almond extract, replace it with vanilla but expect a slightly different flavor.
White chocolate can be replaced with milk or dark chocolate if preferred.
Store in an airtight container at room temperature for 3–4 days or freeze up to three months; thaw before serving.
Use a light-colored metal pan for best results. If you must use glass, reduce oven temperature by 25°F and allow additional baking time.
Nutrition Information:
Yield:
16
Serving Size:
1
Amount Per Serving:
Calories: 311Total Fat: 15gSaturated Fat: 8gTrans Fat: 0gUnsaturated Fat: 6gCholesterol: 49mgSodium: 65mgCarbohydrates: 41gFiber: 0gSugar: 29gProtein: 3g
The nutrition information is an estimate and may vary based on ingredients and portion sizes.
Did you make this recipe?
Please pin or share a photo on Instagram and tag @twosugarbugs — thank you!