Soft and Chewy Funfetti Bars from Scratch (No Cake Mix)

These Soft and Chewy Funfetti Bars are made completely from scratch - no cake mix, no shortcuts, just real butter, a chewy cookie base, and rainbow sprinkles that actually hold their color when baked. A swirled tri-color buttercream frosting takes them from simple homemade funfetti bars to full-on celebration-worthy dessert. Perfect for birthday parties, bake sales, or any time you need a crowd-pleasing dessert bar that looks as good as it tastes.

Love Bars? Try 4 Ingredient Lucky Charm Bars and Monster Cookie Bars.

I've made funfetti bars with cake mix. Everyone has. They're fine - a little spongy, a little one-note, and they taste exactly like what they are: a shortcut. A few years ago I decided to figure out what a truly from-scratch version could taste like, and after about six test batches, I landed on something that made the boxed version feel embarrassing by comparison.

The difference comes down to three things: real butter creamed properly, one whole egg plus an extra yolk for chew without cakiness, and rainbow jimmies (not nonpareils - more on that shortly) folded in right before the batter hits the pan. The result is a chewy funfetti bar with crisp golden edges, a dense and fudgy center, and enough structural integrity to hold a full swirl of tri-color buttercream without collapsing under the weight.

These are the funfetti bars from scratch I bring to every birthday, every bake sale, and every occasion that calls for something that looks festive without requiring a layer cake. They slice cleanly, they travel well, and they disappear fast - every single time.

Soft and Chewy Funfetti Bars for Parties and Birthdays

Too many funfetti bars over‑bake at the edges and turn rock‑hard by day two. This version stays tender and gooey for days, with that rich cake‑batter flavor and a satisfying bar texture instead of basic sheet cake. Very similar to Monster Cookie Bars texture.

Made from scratch, with buttercream frosting (also check Lofthouse Cookies, frosted with colored buttercream as well), and a generous handful of teal, purple and pink sprinkles in both layers, these are the kind of funfetti bars people beg you to bring again for birthdays and parties!

Why From Scratch Matters Here

This is the viral Funfetti Bars formula: made from scratch cookie batter base, REAL butter, creamy topping, and rainbow sprinkles baked into every layer - a genuine from-scratch technique.

• Egg yolk vs. whole egg: Using one whole egg + one yolk (instead of two whole eggs) gives the bars a richer, fudgier center rather than a cakey texture.
• Melted vs. creamed butter: Melted butter creates a denser, chewier bar; creamed butter makes it more cake-like. This recipe uses melted butter intentionally.
• Sprinkle selection: Jimmies (the long cylindrical sprinkles) hold their color in the oven - nonpareils (the tiny balls) bleed purple-gray. You can buy jimmy sprinkles online or in a grocery store.

Funfetti Bars Key Ingredients

• Butter: Softened butter is creamed with sugar to create air pockets, giving the bars a tender, light crumb and rich, buttery flavor.
• White sugar: Balances sweetness and structure so the bars set properly and don't become overly dense.
• Eggs: oOe egg + one yolk produces a chewier bar than two whole eggs.
• Vanilla: Deepens the classic funfetti flavor; vanilla bean paste or extract keeps the flavor warm and bakery‑style.
• All‑purpose flour: Forms the structure of the bars; too much leads to dry, crumbly bars, while too little makes them greasy and underbaked.
• Baking powder and soda: A small amount of both gives the bars a slight lift so they're soft instead of dense and heavy.
• Salt: Balances sweetness and enhances the buttery, vanilla notes so the bars taste complex, not flat.
• Rainbow sprinkles: Assorted sprinkles (stars, edible glitter, nonpareils, etc.) that keep their color and shape when baked; they create the funfetti look without bleeding.
• Buttercream Frosting: Powdered sugar, heavy cream, a pinch of salt and butter.
• Gel food coloring: Pink, Purple, Teal.

How to Make Funfetti Bars from Scratch

This is an overview with step-by-step photos. Full ingredients, measurements & instructions are in the recipe card below.

1. Combine Dry Ingredients

In a medium bowl, whisk together the flour, baking powder, baking soda, salt. Make sure to measure flour correctly - spoon flour into your measuring cup and level it off with a knife. Scooping directly from the bag packs in up to 20% more flour, which dries out the bars.

2. Add Wet Ingredients into Dry

Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix.

• Stop mixing the moment no dry flour is visible - overmixing develops gluten, which makes bars tough and dense in the wrong way rather than chewy in the right way
• The batter will be thick - thicker than cake batter, closer to cookie dough. That's exactly right

3. Add Sprinkles

Gently fold in the sprinkles with a silicone spatula.

4. Spread the Batter into the Pan

Spread the thick batter evenly into a parchment-lined 9×13 inch pan and bake. Line your pan with parchment and leave overhang on two sides - this creates a sling so you can lift the entire slab out cleanly before slicing. Without it, cutting in the pan destroys your corners and edges.

For a thicker, fudgier bar use an 8×8 pan. For thinner, crispier bars use a 9×13, like I did - great for parties and larger crowds!

5. Bake

Bake for 25-30 minutes, or until the edges are lightly golden and a toothpick inserted into the center comes out clean (a few crumbs are fine).  Let the bars cool completely in the pan on a wire rack.

• Don't overbake - pull the bars when the edges are set and golden but the center still looks very slightly underdone. A toothpick should come out with moist crumbs, not wet batter and not clean. The bars continue cooking from residual heat as they cool
• Rotate the pan halfway through baking if your oven runs hot on one side

6. Make the Frosting

Beat softened butter on medium-high speed for about 2 minutes until light and fluffy - this step is key for a creamy, non-dense frosting. Gradually add sifted powdered sugar one cup at a time, beating well after each addition.

Mix in the vanilla, salt, and 2 tablespoons of cream and beat until smooth and fluffy. If the frosting feels too stiff to spread, add more cream one teaspoon at a time until it reaches a soft, pipeable consistency.

7. Divide the Frosting

Divide the buttercream evenly among three small bowls. I did this because I used 3 different colors for the frosting.

8. Color the Frosting

Add a drop of pink gel food coloring to one bowl, purple to another, and teal to the third. Stir each until the color is vibrant and evenly distributed.

9. Frost the Bars

Once the bars are completely cool, you can frost them. Dollop spoonfuls of the pink, purple, and teal frostings randomly over the surface of the cooled bars.

10. Swirl the Frosting Colors

Using an offset spatula or the back of a large spoon, gently swirl the colors together to create a marbled effect. Don't over do it because the colors will be muddy. You want distinct patches and swirls of each color.

11. Add Sprinkles on Top of Frosting

Sprinkle generously with your sprinkles.

12. Cut into Squares

Once the frosting is set, use the parchment paper overhangs to lift the bars out of the pan. Cut into squares or rectangles.

• Do not slice warm - warm bars compress and tear under the knife. Full cooling takes at least 1 hour at room temperature
• For the cleanest cuts, refrigerate for 1 hour after cooling, then use a sharp chef's knife run under hot water, wiped dry between every single cut
• Press straight down - don't saw. One clean downward press per cut gives you sharp, bakery-clean edges

Want to adapt this dough for different pans and flavors? Check out my full guide, How to Make Cookie Bars (and Other Easy Dessert Bars), for pan sizes, bake times, and mix‑in ideas.

Pro Tips for the Best Funfetti Bars

• Use melted butter, not softened - melted butter skips the creaming process, which means less air in the batter and a denser, chewier bar. Creamed butter makes it cakey
• The extra egg yolk is intentional - one whole egg + one yolk adds richness and fat without the additional protein from a second white, which would tighten the structure and make the bars tough
• Don't skip the vanilla - real vanilla extract (not imitation) is what gives from-scratch funfetti bars their signature bakery flavor. Vanilla bean paste works even better if you have it
• Let the melted butter cool for 5 minutes before adding the eggs - adding eggs to hot butter scrambles them
• Once you add the flour, mix only until it's just combined. Overmixing can lead to tougher bars.
• Don't overbake: Pull the funfetti bars from the oven when the edges are set and lightly golden but the center still looks soft; they continue to cook as they cool and will firm up.
• Make sure the base is completely cooled before frosting. Frosting warm bars will lead to melted, sad frosting.
• Chill for cleaner slices: For ultra‑neat edges, chill the cooled funfetti bars in the fridge briefly before slicing, then let them come back to room temperature for serving.

FAQ

• Can I make funfetti bars without cake mix? → Yes - this recipe is entirely from scratch using pantry staples. The result is chewier, richer, and more flavorful than cake-mix versions.
• What kind of sprinkles should I use in funfetti bars? → Use jimmies (rod-shaped), not nonpareils (tiny balls). Nonpareils bleed color into the batter and turn it gray.
• Why do my funfetti bars come out cakey instead of chewy? → This happens when two whole eggs are used. One egg + one yolk keeps the texture fudgy and dense.
• Can I use a Funfetti cake mix instead? → You can, but the texture will be more cakey than chewy. This from-scratch version gives you more control over thickness and chew.

From Scratch vs. Cake Mix

Most funfetti bar recipes you'll find online start with a box of Funfetti cake mix. It's fast, it's easy, and the results are perfectly fine. But if you've ever made them and thought "these are a little cakey" or "something's just missing" - you're not imagining it.

Boxed version funfetti bars taste artificially flavored, often overly sweet and you have little control over flavor, while funfetti bars made from scratch are thicker, more balanced in flavor and hold sprinkles better.

The bottom line: If you want bars that are chewy, rich, and taste like a real bakery made them - this from-scratch version is worth the extra 10 minutes. The cake mix gets you there faster; scratch baking gets you there better!

How do I get clean cuts on funfetti bars?

The secret to clean, bakery-style cuts is cold bars and a hot knife. Follow these steps every time:

1. Chill completely first - refrigerate the fully baked and cooled bars for at least 1 hour before slicing. Cold bars hold their shape and don't compress or drag under the knife. Trying to cut them warm is the #1 reason for ragged, uneven edges
2. Use a sharp chef's knife - not a serrated bread knife. A straight-edge blade cuts cleanly through the dense, chewy layers; a serrated blade tears them
3. Run the knife under hot water - hold it under hot tap water for 10 seconds, then wipe completely dry with a paper towel before each cut
4. Use one firm downward press - don't saw back and forth. Press straight down and pull the knife out cleanly before moving to the next cut
5. Wipe the blade between every single cut - otherwise sprinkles stick to the blade and drag into the next slice if you don't clean it each time

Storage

Store leftover bars in an airtight container at room temperature for up to 3 days, or in the fridge for up to 5 days (let come to room temperature slightly before serving if refrigerated, as the base will be firmer).

Can I Freeze Them? Fully baked and cooled bars can be frozen for up to 3 months.

More Sweet Bars to enjoy

• Raspberry Swirl Lemon Bars
• Cranberry Bliss Bars
• Strawberry Crumb Bars
• Cranberry Pecan Bars