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Kawaii but realistic cotton candy marshmallow blondies with pastel pink and blue color baked throughout, stacked bars showing gooey marshmallow pieces inside on a soft pastel background.
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🍬 Cotton Candy Marshmallow Blondies

Soft and chewy cotton candy marshmallow blondies with a buttery vanilla base, swirled pastel color, and pockets of gooey melted marshmallows. These whimsical dessert bars capture classic cotton candy flavor in a rich blondie form, baking up crisp on the edges and irresistibly soft in the center—perfect for parties, bake sales, or anytime you want a fun, carnival-inspired treat.
Course Bake Sale Treats, Bars, Dessert
Cuisine American
Keyword carnival dessert, cotton candy blondies, cotton candy marshmallow blondies, marshmallow blondies, pastel dessert bars, sweet blondie bars, whimsical baking
Prep Time 15 minutes
Cook Time 26 minutes
Total Time 45 minutes
Servings 9 large blondies
Calories 340kcal
Cost $7 for entire recipe

Equipment

  • 8×8 inch baking pan
  • Parchment paper
  • Mixing bowls
  • Whisk
  • Rubber spatula
  • measuring cups
  • Measuring spoons
  • Knife or skewer (for swirling batter)

Ingredients

Blondie Base

  • ¾ cup 150 g light brown sugar, packed
  • ¼ cup 50 g granulated sugar
  • ½ cup 113 g unsalted butter, melted & cooled
  • 1 large egg + 1 egg yolk room temperature
  • 1½ tsp cotton candy extract
  • 1 tsp vanilla extract
  • 1 cup 125 g all-purpose flour
  • ½ tsp baking powder
  • ¼ tsp fine salt

Mix-Ins & Swirl

  • 1½ cups mini marshmallows
  • Pink & blue gel food coloring optional
  • ½ cup cotton candy–flavored baking chips or white chocolate chips optional

Instructions

  • Prep: Preheat oven to 350°F (175°C). Line an 8×8-inch pan with parchment, leaving overhang.
  • Mix sugars & butter: Whisk melted butter with brown and granulated sugars until smooth and glossy.
  • Add eggs & flavor: Whisk in egg, yolk, cotton candy extract, and vanilla until fully combined.
  • Dry ingredients: Fold in flour, baking powder, and salt just until no dry streaks remain.
  • Color (optional): Divide batter in half. Tint one pink and one blue.
  • Layer & swirl: Spoon alternating dollops of pink and blue batter into pan. Lightly swirl with a knife.
  • Top it off: Sprinkle marshmallows and chips evenly over the top; gently press in.
  • Bake: 22–26 minutes, until edges are set and center looks just barely underbaked.
  • Cool: Let cool completely before slicing for clean cuts.

Notes

  • Cotton candy extract strength varies by brand. If yours is very concentrated, start with 1 teaspoon and increase slightly in the next batch if needed.
  • Do not overbake. The center should look slightly underdone when removed from the oven; it will finish setting as it cools and stay chewy instead of cakey.
  • Marshmallow placement matters. Press marshmallows lightly into the batter so they melt into pockets instead of fully dissolving on top.
  • For extra gooey tops, add a small handful of marshmallows during the last 5 minutes of baking.
  • Color gently. Gel food coloring is best—liquid coloring can thin the batter and affect texture.
  • Clean slices tip: Let blondies cool completely, then wipe your knife between cuts for neat edges.
  • Storage: Keep in an airtight container at room temperature for up to 2 days or refrigerate up to 5 days. Bring to room temperature before serving for best texture.
  • Freezing: Blondies freeze well for up to 2 months; wrap individually to prevent marshmallow sticking.