How to Turn a Boxed Cake Mix into Whoopie Pies

Learn how to turn a boxed cake mix into soft, fluffy whoopie pies with this easy step-by-step guide.

How to Turn a Boxed Cake Mix into a Whoopie Pie pin for Pinterest

If you love soft cookies and creamy fillings, you're going to adore homemade whoopie pies! The best part? You don't have to start from scratch. With a simple boxed cake mix and a few pantry staples, you can create bakery-style sandwich cookies in just a fraction of the time.

Whether you're craving classic whoopie pies, nostalgic sandwich cookies, or even homemade Cakesters, this easy method will open up a whole new world of baking possibilities.

What Is a Whoopie Pie?

whoopie pies on plate (red velvet whoopie pies)

Whoopie pies have long been associated with Pennsylvania Dutch and Amish baking, where they're considered a beloved homemade treat. Several regions—including Maine—claim to have invented them, but no matter where they originated, they've become one of America's favorite handheld desserts.

Traditionally, a whoopie pie consists of two soft, cake-like rounds sandwiched together with a fluffy filling, often marshmallow or vanilla frosting. They're tender, moist, and much softer than a typical cookie.

red velvet whoopie pies with cream cheese filling

So What's the Difference Between a Whoopie Pie and a Sandwich Cookie?

People often use the terms interchangeably, but there is a subtle difference.

A whoopie pie is usually made with very soft, cake-like cookies or small rounds of cake. They're thick, pillowy, and almost melt in your mouth.

A sandwich cookie is the broader category. It simply means two cookies with a filling in the middle. Some are crisp (like Oreos), while others are soft and chewy, like my Oatmeal Cream Pies or German Chocolate Sandwich Cookies.

In other words...

Every whoopie pie is a sandwich cookie—but not every sandwich cookie is a whoopie pie.

Since many of my recipes begin with doctored cake mix cookie dough, you'll find both styles here on Out of the Box Baking. Some are true whoopie pies, while others lean more toward soft sandwich cookies. Either way, they're delicious!

What About Cakesters?

If you've ever enjoyed an Oreo Cakester, you've already tasted something very similar to a whoopie pie.

Cakesters feature two soft, cake-like chocolate cookies filled with sweet cream, making them much closer to a miniature whoopie pie than a traditional crunchy sandwich cookie.

If you're feeling nostalgic, be sure to check out my homemade Lemon Cakesters!

Why Cake Mix Works So Well

One of my favorite baking shortcuts is starting with a boxed cake mix. It creates soft, tender cookies with very little effort, making it the perfect base for homemade sandwich cookies.

ingredients for whoopie pies or Cakesters

Instead of measuring flour, baking powder, spices, and sugar separately, the cake mix does most of the work for you. That means less measuring, less cleanup, and consistently delicious results.

How to Turn Cake Mix Cookies into Whoopie Pies

The process couldn't be easier.

Step One: Bake Soft Cookies

Choose one of your favorite cake mix cookie recipes and bake the cookies according to the recipe instructions. Here's the general conversion to turn a cake mix into a soft cookie:

1 box cake mix (any flavor)
½ cup oil (or melted butter)
1-2 eggs (check the individual recipes)

For the best whoopie pies, look for cookies that are soft and cake-like rather than crisp or crunchy.

Allow them to cool completely before filling.

Step Two: Match Similar Sizes

soft cookies flipped upside-down on tray ready to be filled

Lay the cookies out on your countertop and pair cookies that are close in size.

This simple step gives your finished sandwiches a much more professional appearance.

Step Three: Add Your Filling

whoopie pies being filled with buttercream

Now comes the fun part!

Pipe or spread your favorite filling onto the flat side of one cookie before topping it with its partner.

Some of my favorite fillings include:

Chocolate ganache
Whipped chocolate ganache
Vanilla buttercream
Chocolate buttercream
Marshmallow frosting
Peanut butter frosting
Cream cheese frosting
Lemon buttercream

Don't be afraid to mix and match flavors. Chocolate and orange, pumpkin and chocolate, strawberry and vanilla, and peanut butter with chocolate are all wonderful combinations.

Step Four: Let Them Rest

Once assembled, allow the sandwiches to rest for 30 to 60 minutes before serving.

This gives the filling time to set and allows all of the flavors to come together beautifully.

My Favorite Cake Mix Whoopie Pie Recipes

If you're looking for inspiration, here are some reader favorites from Out of the Box Baking:

I'm always experimenting with new flavors, so check back often! I have several more cake mix sandwich cookies and whoopie pies in the works.

Tips for Success

Use a cookie scoop so all of your cookies are the same size.

Allow the cookies to cool completely before adding the filling.

Pipe the filling instead of spreading it for a prettier presentation.

If using ganache, allow the finished sandwiches to chill briefly before serving.

Store the cookies in an airtight container to keep them soft and fresh.

Let's Explore the "How to Turn a Boxed Cake Mix..." Series

Click any guide below to discover a new way to transform an ordinary boxed cake mix into something extraordinary.

Cake Mix Transformation Cheat Sheet

Every transformation on this site begins with the same simple idea: change the ingredients, change the result. Here's a quick reference showing the basic formula behind each type of cake mix creation.

Want to Make...	Basic Formula	The Result
🍰 Cake	Follow the box directions (then doctor as desired)	Light, fluffy traditional cake.
🧈 Pound Cake	4 eggs + butter/oil + milk + pudding	Rich, dense, buttery crumb.
🧁 Cupcakes	Doctored cake batter	Bakery-style cupcakes with tender crumb.
🍪 Cookies & Whoopie Pies	2 eggs + ½ cup butter	Thick dough for soft, chewy cookies.
🍫 Brownies	2 eggs + ½ cup butter	Dense, fudgy brownies.
🍋 Dessert Bars	1 egg + ½ cup butter	Press-in dough with a shortbread-style crust.
🥐 Pastries	Enriched dough (see guide)	Flaky pastries, scones, pinwheels, kolaches, and more.
🍞 Quick Breads	3 eggs + butter + mashed fruit or sour cream	Moist loaf cakes with bakery texture.
🧁 Muffins	2 eggs + butter + about ¾ cup liquid	Tender, bakery-style muffins.
🍥 Cinnamon Rolls	Yeast + cake mix dough	Soft, fluffy cinnamon rolls.
🎂 Cake Bites	2 eggs + ½ cup butter (+ splash of liquid if needed)	Soft, bite-sized treats perfect for parties.
💝 Petit Fours	Thin sheet cake + coating	Elegant bite-sized desserts for celebrations.

Frequently Asked Questions

Are whoopie pies actually pies?

Not at all! Despite the name, they're really soft cake-like sandwiches filled with frosting or cream.

Can I make whoopie pies with a boxed cake mix?

Absolutely! In fact, that's one of my favorite shortcuts. Cake mix produces wonderfully soft cookies that are perfect for sandwiching together.

What's the best filling for whoopie pies?

Classic marshmallow filling is always popular, but buttercream, whipped ganache, chocolate frosting, peanut butter frosting, and cream cheese frosting are all delicious choices.

Can I freeze whoopie pies?

Yes! Wrap each sandwich individually and freeze for up to three months. Thaw overnight in the refrigerator or on the counter before serving.

Do whoopie pies need to be refrigerated?

That depends on the filling. Buttercream and ganache are generally fine for short periods at room temperature, while cream cheese fillings should be refrigerated.

What cake mix flavors work best?

Almost any flavor! Chocolate, lemon, strawberry, spice, red velvet, German chocolate, carrot cake, peanut butter, and pumpkin all make wonderful sandwich cookies.

Final Thoughts

Whoopie pies are one of those desserts that look like they came from a bakery but are surprisingly simple to make at home. Starting with a boxed cake mix makes the process even easier, giving you soft, tender cookies that are perfect for filling with your favorite frosting or ganache.

Whether you call them whoopie pies, sandwich cookies, or even homemade Cakesters, these sweet little treats are guaranteed to disappear fast!