If you have a soft spot for classic sweets that combine simplicity with vibrant nostalgia, then this Frosted Sugar Cookie Bars Recipe is a total must-try. Imagine the buttery, tender cookie base studded with joyful rainbow sprinkles and smothered in a luscious, creamy frosting that melts in your mouth. This recipe captures all the charm of your favorite sugar cookies but saves time by transforming them into easy-to-cut bars, perfect for parties, gifts, or just a delightful snack any day of the week.

Ingredients You’ll Need

The image shows several square pieces of a two-layer dessert on a white marbled surface. The bottom layer is a thick, dense cake with colorful sprinkles mixed inside, showing a yellowish texture with bright specks of blue, green, and red. The top layer is a thick, smooth, and light pink frosting, evenly spread with a creamy texture. On top of the frosting, there are various colorful round and tiny sprinkle decorations in shades of yellow, orange, purple, green, blue, white, and red, scattered generously. The pieces are neatly cut and arranged close together. photo taken with an iphone --ar 4:5 --v 7

This recipe is a wonderful example of how a handful of everyday ingredients can come together to create pure magic. Each element plays a key role, from the creamy butter that ensures richness, to the sprinkles that bring that burst of cheerfulness and texture, not to mention the smooth frosting that finishes the bars with a sweet, velvety touch.

1/2 cup (8 Tbsp; 113g) unsalted butter, softened to room temperature: This helps create that tender, melt-in-your-mouth cookie texture.
3/4 cup (150g) granulated sugar: Adds the perfect amount of sweetness and helps give the bars a slight crunch on top.
1 large egg + 1 egg yolk: The yolk adds extra richness and chewiness to the cookie base.
2 teaspoons pure vanilla extract: Infuses that classic warm, aromatic flavor we all love in sugar cookies.
1 and 1/2 cups (188g) all-purpose flour (spooned & leveled): The foundation for these bars’ structure and softness.
1/4 teaspoon salt: Balances sweetness and elevates the overall flavor.
1 teaspoon baking powder: Adds a gentle lift to keep the bars light and airy.
1/2 teaspoon baking soda: Works with the acidic ingredients to ensure the perfect texture.
1 and 1/2 teaspoons cornstarch: Keeps the cookie bars tender and crumbly.
1/2 cup (80g) rainbow sprinkles (not nonpareils): These bring color and festive fun inside the bars.
3/4 cup (12 Tbsp; 170g) unsalted butter, softened to room temperature (for frosting): Gives the frosting its rich, creamy base.
2 and 1/4 cups (270g) confectioners’ sugar: Sweetens and thickens the frosting perfectly.
3 Tablespoons (45ml) heavy cream or half-and-half: Adds smoothness and helps adjust frosting consistency.
1 teaspoon pure vanilla extract: Enhances the frosting’s flavor with aromatic warmth.
Salt, to taste (for frosting): Cuts sweetness and balances the flavors.
Optional: food coloring and extra sprinkles for decoration: Customize your frosting color and add a little sparkle on top.

How to Make Frosted Sugar Cookie Bars Recipe

Step 1: Preheat and Prepare Your Pan

Start by preheating your oven to 350°F (177°C). It’s important to line your baking pan—either 8-inch or 9-inch square—with aluminum foil. Be sure to leave enough foil hanging over the sides to help lift the bars out easily after baking. This preparation sets you up for effortless cleanup and pristine bars.

Step 2: Cream Butter and Sugar

In a large bowl with your mixer, cream the softened butter until it’s silky smooth, about a minute on medium speed. Then, add the granulated sugar and continue beating until the mixture is fluffy and light in color. This step is key for creating that tender, soft crumb everyone adores. Next, blend in the egg, extra egg yolk, and vanilla to infuse richness and flavor.

Step 3: Combine Dry Ingredients

Whisk the flour, salt, baking powder, baking soda, and cornstarch together in a separate bowl. This ensures everything is evenly mixed, which helps your bars bake evenly. Add the dry mix to the wet ingredients in three parts, gently mixing on low speed to avoid overworking the dough. The dough will be thick, which is exactly what you want.

Step 4: Fold in the Sprinkles and Press into Pan

Now for the fun part—fold 1/2 cup of rainbow sprinkles into the thick dough, distributing those pops of color throughout. Transfer the cookie dough into your prepared pan and press it evenly to form a smooth, level surface. This creates the perfect base for your sugary confection.

Step 5: Bake to Tender Perfection

Bake the cookie bars for 25 to 26 minutes until the top is just barely golden. Avoid overbaking at all costs; you want these bars ultra-soft rather than crunchy. Once out of the oven, cool completely on a wire rack. The center might sink slightly—that’s perfectly normal and part of their charm.

Step 6: Make the Frosting

While the bars cool, whip up the frosting. Beat the softened butter until creamy, then gradually add the confectioners’ sugar, cream, and vanilla on low speed. Increase to high and whip for a full 3 minutes for a light, fluffy result. Adjust thickness by adding more sugar or cream as needed. Add a pinch of salt to balance sweetness, and if you want a splash of color, mix in food coloring at this stage.

Step 7: Frost and Decorate

Lift the cooled cookie bars out of the pan using the foil overhang. Spread a generous layer of frosting over the top, then decorate with extra sprinkles if you like. Cut the bars into neat squares with a sharp knife, wiping the blade between cuts for clean edges. Your Frosted Sugar Cookie Bars Recipe is now ready to enjoy!

How to Serve Frosted Sugar Cookie Bars Recipe

A close-up of small square cake pieces with two visible layers: the bottom layer is a light yellow cake with colorful sprinkles mixed inside, and the top layer is a thick, smooth pink frosting covered with a mix of small, round, bright-colored sprinkles and larger flat confetti sprinkles in various colors. The cake pieces sit on a white plate placed on a white marbled surface. Photo taken with an iphone --ar 4:5 --v 7

Garnishes

For that extra special touch, top your frosted bars with a few additional sprinkles or even colorful sanding sugar. Fresh berries or edible flowers can also add a surprisingly elegant flair that contrasts beautifully with the playful sprinkles.

Side Dishes

These bars stand wonderfully on their own but also pair like a dream with a cold glass of milk, a hot cup of coffee, or a mild tea. For a fun dessert platter, include a scoop of vanilla or strawberry ice cream alongside to create a delightful treat.

Creative Ways to Present

Try serving these bars on a decorative plate with a dusting of powdered sugar for a simple yet elegant presentation. For holiday occasions, customize the frosting color and sprinkle theme to match the event. Cut the bars into bite-size pieces for party platters, or stack them for an instagram-worthy dessert tower.

Make Ahead and Storage

Storing Leftovers

Keep any leftover Frosted Sugar Cookie Bars Recipe in an airtight container at room temperature for up to two days. If you want them to last longer, refrigeration is a great option and can keep the bars fresh for up to five days. Always make sure they’re well covered to prevent the frosting from drying out.

Freezing

If you want to make these bars ahead of time for a bigger event, they freeze beautifully. Wrap them tightly in plastic wrap and place in a freezer-safe bag or container. They can be frozen for up to three months. When ready to enjoy, thaw overnight in the refrigerator for the best texture.

Reheating

To bring back that just-baked warmth, let the bars come to room temperature after refrigeration or thawing. If you want the soft texture and slightly melty frosting experience, warm individual squares in the microwave for about 10 to 15 seconds. Just watch closely to avoid melting the frosting too much.

FAQs

Can I use different types of sprinkles in this recipe?

Absolutely! While rainbow sprinkles work wonderfully for that classic look and texture, you can experiment with your favorite sprinkle types as long as they’re similar in size and won’t bleed color. Avoid nonpareils as they tend to sink and bleed too much during baking.

Is it possible to make these bars gluten-free?

Yes, you can swap out the all-purpose flour for a gluten-free blend that measures 1:1 for flour in baking. Look for a good quality mix that contains xanthan gum to ensure the right texture. Your bars will still be delicious and soft.

How thick should I frost the bars?

This depends on your preference! The original recipe calls for a thick frosting layer, which makes these bars extra decadent. If you prefer a lighter touch, you can halve the frosting recipe or spread a thinner layer. Both ways taste fantastic.

Can I make the frosting vegan?

Definitely! Use vegan butter substitutes and a plant-based milk or cream alternative like coconut cream for whipping the frosting. Make sure your vanilla extract is pure and check that your powdered sugar is vegan-friendly. This way, everyone can enjoy these delightful bars.

What’s the best way to cut neat squares without smudging the frosting?

Use a very sharp knife and wipe the blade clean with a paper towel between each cut. This keeps the frosting edges crisp and pretty, creating clean, photo-ready squares every time.

Final Thoughts

I genuinely can’t recommend this Frosted Sugar Cookie Bars Recipe enough because it strikes that perfect balance between nostalgic comfort and easy-going fun. Whether you’re bringing them to a celebration or indulging in a quiet moment with a cup of tea, these bars are bound to brighten your day. Give this recipe a go—you’ll likely find yourself making them again and again, just like I do!