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Birthday cake–flavored vanilla fudgy brownies with a glossy crackled top, rainbow sprinkles, and a dense, chewy interior sliced into squares.
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Birthday Cake–Flavored Vanilla Fudgy Brownies

Ultra-fudgy vanilla brownies infused with birthday cake flavor, featuring chewy edges, a glossy top, and a rich, dense center—pure brownie texture with nostalgic cake-batter sweetness, not cake-like or fluffy.
Course Dessert, Party Treat, Snack
Cuisine American
Keyword birthday cake brownies, birthday dessert bars, brownie bars, cake batter brownies, chewy vanilla brownies, funfetti brownies, vanilla brownies, vanilla fudgy brownies
Prep Time 15 minutes
Cook Time 32 minutes
Cool time 1 hour
Servings 16 brownies
Calories 300kcal
Cost $9 for entire recipe

Equipment

  • 8×8 inch baking pan
  • Parchment paper
  • Large mixing bowl
  • Whisk
  • Rubber spatula
  • measuring cups
  • Measuring spoons
  • Oven
  • Cooling rack
  • Knife for slicing

Ingredients

Wet Ingredients

  • ¾ cup 170 g unsalted butter, melted and slightly cooled
  • 1¼ cups 250 g granulated sugar
  • 2 large eggs + 1 egg yolk room temperature
  • 1½ teaspoons vanilla extract
  • 1 teaspoon cake batter extract OR birthday cake extract
  • ½ teaspoon butter extract optional
  • ¼ teaspoon almond extract optional but recommended
  • 2 tablespoons heavy cream or whole milk

Dry Ingredients

  • ¾ cup 95 g all-purpose flour
  • ½ teaspoon salt

Mix-Ins

  • ¼ cup white chocolate chips optional
  • ¼ cup rainbow jimmies not nonpareils

Instructions

Prep pan

  • Preheat oven to 325°F (165°C). Line an 8×8 pan with parchment.

Create glossy brownie base

  • Whisk melted butter and sugar vigorously for 30–45 seconds until thick and glossy.

Add eggs & flavoring

  • Whisk in eggs and yolk one at a time until smooth and shiny. Stir in vanilla extract, chosen cake extract, optional butter extract, almond extract, and cream.

Fold in dry ingredients

  • Gently fold in flour and salt just until combined. Do not overmix.

Add mix-ins

  • Fold in white chocolate chips and sprinkles last.

Bake

  • Spread batter evenly. Bake 28–32 minutes, until edges are set and the center looks slightly underbaked.

Cool completely

  • Cool in pan for 1 hour before slicing for maximum fudginess.

Notes

  • These are brownies, not blondies.
    The high butter-to-flour ratio, extra yolk, and low bake temperature create a dense, fudgy structure even without cocoa.
  • Choose ONE specialty extract only.
    Cake batter extract = richer, bakery-style flavor.
    Birthday cake extract = sweeter, nostalgic boxed-cake flavor.
    Using both muddies the flavor.
  • Butter extract is optional, not required.
    Use it only if your cake/birthday extract tastes flat. Skip if your extract brand is strong.
  • Whisking butter and sugar is critical.
    This step creates the shiny brownie top normally formed by dissolved cocoa solids. Don’t rush it.
  • Egg yolk = fudginess.
    The extra yolk adds richness and prevents a cakey crumb. Do not substitute with whole egg.
  • Do not add baking powder or soda.
    Any leavening will push these into cake or blondie territory.
  • Use rainbow jimmies only.
    Nonpareils bleed color and create a gritty texture.
  • Slight underbake is intentional.
    Pull the brownies when the center looks just set but soft — they firm up as they cool.
  • Cool completely before slicing.
    Cutting early will make them seem underbaked and greasy rather than fudgy.
  • For cleaner cuts:
    Chill brownies for 20–30 minutes, then slice with a warm knife.
  • Photo tip:
    A center pull or stacked edge shot communicates “brownie” better than a flat overhead for vanilla versions.