Perfect Pastel Halloween Swirled Funfetti Cookie Bars with Buttercream
Bright, sweet, and just a bit messy pastel Halloween swirled funfetti cookie bars topped with silky smooth buttercream frosting. Quick and easy to make, perfect for festive gatherings and kids’ parties.
- Prep Time: 15 minutes
- Cook Time: 25 minutes
- Total Time: 40 minutes
- Yield: 12 servings 1x
- Category: Dessert
- Cuisine: American
Ingredients
- 1 cup (226 g) unsalted butter, softened (for cookie bars)
- 3/4 cup (150 g) granulated sugar
- 1/2 cup (100 g) packed brown sugar
- 2 large eggs, room temperature
- 2 teaspoons pure vanilla extract
- 2 1/4 cups (280 g) all-purpose flour
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
- 3/4 cup (120 g) pastel Halloween-themed sprinkles (Wilton’s pastel mix recommended)
- Gel food coloring in pastel tones (pink, purple, mint green, pale orange)
- 1 cup (226 g) unsalted butter, softened (for buttercream frosting)
- 3 to 4 cups (360–480 g) powdered sugar, sifted
- 1 teaspoon pure vanilla extract
- 2 to 3 tablespoons (30–45 ml) whole milk or heavy cream
- Gel food coloring in pastel shades (same as batter)
Instructions
- Preheat oven to 350°F (175°C). Grease or line a 9×13 inch baking pan with parchment paper, leaving overhang for easy removal.
- In a large bowl, cream 1 cup softened unsalted butter with 3/4 cup granulated sugar and 1/2 cup brown sugar using an electric mixer until light and fluffy (3-4 minutes).
- Beat in 2 large eggs one at a time, then stir in 2 teaspoons vanilla extract until just combined.
- In a separate bowl, whisk together 2 1/4 cups all-purpose flour, 1/2 teaspoon baking soda, and 1/2 teaspoon salt.
- Gradually add dry ingredients to wet mixture, mixing on low speed or folding gently until just combined.
- Divide dough evenly into four small bowls. Add a few drops of gel food coloring to each (pink, purple, mint green, pale orange) and gently fold to create visible streaks.
- Dollop spoonfuls of each colored dough alternately across the prepared pan. Use an offset spatula or butter knife to gently swirl the colors together to create a marbled pastel effect without overmixing.
- Sprinkle 3/4 cup pastel Halloween-themed sprinkles evenly over the top, pressing lightly to stick.
- Bake for 22-25 minutes until edges are golden and a toothpick inserted near the center comes out with a few moist crumbs. Start checking at 20 minutes to avoid overbaking.
- Cool cookie bars completely in the pan for at least 30 minutes before frosting.
- For the buttercream, beat 1 cup softened unsalted butter until creamy (about 2 minutes). Gradually add 3 to 4 cups powdered sugar, 1 cup at a time, beating well after each addition.
- Add 1 teaspoon vanilla extract and 2 to 3 tablespoons milk or heavy cream to reach desired spreadable consistency.
- Divide buttercream into small bowls and tint with the same pastel gel colors as the batter. Dollop different colors randomly on a plate or tray.
- Using a spatula, lightly scoop and swirl the colored buttercream together until marbled but not fully mixed.
- Spread the swirled buttercream evenly over the cooled cookie bars.
- Refrigerate frosted bars for 20 minutes to set the buttercream.
- Slice into squares using a sharp knife, wiping the blade between cuts for clean slices.
- Serve chilled or at room temperature.
Notes
Use softened butter, not melted, for best chewy texture. Avoid overmixing after adding flour to prevent toughness. Gel food coloring provides vibrant pastel hues without thinning batter or frosting. Cool bars completely before frosting to prevent melting. Use a sharp knife wiped between cuts for clean slices. For dairy-free, substitute vegan butter and plant-based milk. For gluten-free, use a gluten-free all-purpose flour blend. Bars can be baked in muffin tins for cookie cups with reduced baking time (12-15 minutes).
Nutrition
- Serving Size: 1 bar (1/12th of rec
- Calories: 320
- Sugar: 28
- Sodium: 150
- Fat: 18
- Saturated Fat: 11
- Carbohydrates: 40
- Fiber: 1
- Protein: 3
Keywords: funfetti cookie bars, pastel Halloween cookies, buttercream frosting, easy dessert, swirled cookie bars, festive treats, kid-friendly dessert