bars small batch

birthday cake blondies

these birthday cake blondies taste like a classic buttery blondie. filled with sprinkles and topped with classic vanilla buttercream. these cutie cookie bars are small batch, and perfect for celebrating...anything, anytime!

we are well on our way through may! can you even believe it? I know I can’t! my birthday is coming up and I thought, “you know what sounds good? birthday cookies!” lately, i’ve been in a small batch baking mood- cakes, cookies, brownies, etc. one thing lead to another and these cute little cookie bars came to be! these birthday cake blondies are packed with buttery cookie flavor, sprinkles and are so much fun to eat! here’s why I love them so much!

in a few words, these cookies are

  • buttery
  • sweet
  • chewy
  • slightly cake-y
  • filled with sprinkles
  • topped with classic vanilla buttercream
  • FUN!!
  • make you smile when you eat them

birthday cake blondies

short and sweet ingredient list

the best thing about these birthday cake blondies is basic + minimal ingredient list. aka, make them anytime!

  • all purpose flour
  • baking powder
  • salt
  • unsalted butter
  • light brown sugar
    • granulated sugar also works!
  • egg
  • vanilla extract
    • for the full “birthday cake” taste, just this vanilla
  • powdered sugar
  • milk or heavy cream
  • sprinkles!
birthday cake blondies (small batch)

grab these baking tools for the best small batch blondies!

  • whisk, spatula, small and medium sized mixing bowls
    • to mix the dry and wet ingredients for the birthday cake blondies
  • 9X5 loaf pan
    • this is the preferred size for making these as a “small batch”
    • other pan: 8.5X4.5 loaf pan OR
    • double the recipe and bake in 8X8 or 9X9, 8-9″ pans
  • parchment paper
    • helps to lift the blondies from the pan
  • stand mixer with paddle attachment OR electric mixer with beaters
    • to make the frosting
    • can also use a store bought vanilla frosting!
  • food scale
    • I prefer using this instead of measuring cups
    • makes this recipe one bowl!
    • more accurate for the recipe as it’s written
  • oven thermometer
    • highly recommended no matter how old or new your oven is
    • gives the internal temperature more accurately
    • let’s you know where the hot spots are in the oven
birthday cake blondies (small batch)

tips and tricks for a great birthday cookie bar!

best substitutes for this recipe:

  • all purpose flour: the best sub for this would be a GF 1:1 flour from Bob’s Red Mill
    • use a grain free blondie recipe developed for a 8X8 or 9X9 sized pan
    • cut in half to fit a 9X5 pan
  • baking powder: this can be omitted if needed
  • sugar: light brown sugar or granulated sugar works for this recipe
  • egg: keep the egg if you can, if not use flax egg
    • mix 1 tbsp ground flaxseed with 3 tbsp water
    • let sit 10 minutes
    • use in place of the egg
  • unsalted butter: for a dairy free option, try
    • vegan butter, melted
    • a good, fruity flavored olive oil
  • vanilla buttercream
    • for a vegan option, use this
    • use your favorite store bought version
  • sprinkles: naturally colored sprinkles will most likely lose color while baking
    • these look like a good dye free sub
    • omit the sprinkles IN the blondies, instead
    • TOP the blondies with naturally dyed sprinkles

tips for the best birthday cake blondies

  • use room temperature ingredients
    • butter will be melted, but should cool slightly before mixing with the egg
  • mix the blondies by hand
  • bake until the edges are set
    • the center may look a slightly under baked
  • cool in the pan for 30 minutes
  • the blondies should be completely cooled before frosting
  • buttercream can be made ahead of time
    • store in air tight container in the fridge for 1-2 days or freezer for a month
    • bring to room temperature before using on the blondies
  • have FUN!
birthday cake blondies (small batch)
birthday cake blondies
birthday cake blondies (small batch)

more sprinkle recipes to love!

birthday cake blondies

birthday cake blondies (small batch)

these birthday cake blondies taste like a classic buttery blondie. filled with sprinkles and topped with classic vanilla buttercream. these cutie cookie bars are small batch and perfect for celebrating…anything, anytime!
4.84 from 6 votes
Prep Time 15 mins
Cook Time 30 mins
Cooling Time 30 mins
Total Time 1 hr 15 mins
Course Celebrations, Dessert
Cuisine American


  • large mixing bowl
  • whisk and spatula or medium spoon
  • 9X5 loaf pan
  • parchment paper
  • stand mixer with paddle attachment or electric mixer with beaters (for frosting)


birthday cake blondies

  • 3/4 c (90g) all purpose flour
  • 1/8 tsp "pinch" of baking powder fill a 1/4 tsp measuring spoon halfway
  • 1/2 tsp salt
  • 1/4 c (57g) unsalted butter, melted
  • 1/2 c (100g) light brown sugar sub with granulated sugar
  • 1 (57g) large egg, room temperature
  • 1 tsp (5ml) vanilla extract
  • 1/3 c sprinkles

vanilla buttercream frosting

  • 3 tbsp unsalted butter, room temperature
  • 1 1/2 c (180g) powdered sugar, sifted
  • 1-2 tbsp (15-30ml) milk or heavy cream
  • 1/4 tsp vanilla extract
  • 1 tbsp sprinkles, optional for topping


birthday cake blondies

  • Preheat the oven to 350 F (177C). Line a 9X5 loaf pan with parchment paper along the long sides, leaving a 1-2" overhang). Set aside.
  • In a small bowl, whisk the flour, baking powder and salt together. Set aside.
  • In a medium or large mixing bowl, whisk the melted butter and sugar together until full combined. Add the egg and whisk until smooth. This should take several turns around the pan. Get those arms muscles moving! Whisk in the vanilla extract.
  • Add the dry mixture to the wet. Using a spoon or spatula, stir the dry ingredients into the wet until mostly combined. Add the sprinkles, and mix until fully combined.
    Pour the blondie batter into the prepared pan. Make sure to smooth the batter evenly into the corners and across the pan.
  • Bake at 350 F (177 C) for 28-35 minutes. The blondie is finished baking when the edges are set and pull gently away from the sides of the pan. The top will be golden brown. A toothpick inserted into the center will yield no crumbs (or a very few moist).
    Cool in pan for 30 minutes. Use a butter knife to gently loosen the edges of the blondie that are touching the pan. Using the parchment overhangs, pull the blondies out of the pan. Cool on a cooling rack if topping with the buttercream.

classic vanilla buttercream

  • In a stand mixer, with paddle attachment, place butter, 1/2 cup powdered sugar, vanilla extract and 1 tbsp milk. Beat until smooth and creamy. On low, add 1/4 c powdered sugar at a time. If needed, add 2-3 tsp more milk, one teaspoon at a time. Once smooth and creamy, beat on high until desired frosting consistency is reached. Frosting should be thick and spreadable.
    Top blondie bars right before serving.
Keyword birthday cake blondies, birthday cookie bars, funfetti blondies, small batch cookie bars
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