You’ve been begging for this one—and I’m so excited to finally share it! If you grew up loving those classic vanilla snack cakes with the marshmallowy middle and squiggly white swirls on top, this cake is for you. It’s soft, sweet, nostalgic, and so much better homemade.
Just like my Chocolate Hostess Sheet Cake, this one starts with a doctored cake mix—but this time it’s all vanilla, all the way. We’re using a yellow or white boxed cake mix and adding a few ingredients to make it richer, more tender, and totally worthy of the Hostess name. A layer of marshmallow cream filling gets sandwiched between two cake layers and is finished with those signature white swirls.
Why You’ll Love It
- Doctored cake mix magic – quick, easy, but totally elevated. Also gives that classic snack cake flavor
- Nostalgic – tastes like a homemade version of the vanilla snack cakes
- Marshmallow filling – sweet and not overpowering
- No piping bag? No problem! You can easily just spread the filling on top or leave it plain. It will be just as delicious 🙂
Recipe Tips
Boxed cake mix base. This recipe uses a yellow boxed cake mix, but the magic is in the add-ins. The flour, sugar, sour cream, and vanilla really boost the flavor and texture—don’t skip them! Either yellow or white mix works great here. If using white cake mix, your final cake will be slightly lighter in color but still rich and moist.
Use a metal baking pan. Metal pans bake more evenly than glass and are especially helpful when you’re slicing and layering. I always recommend a 9×13 metal pan—this one’s my favorite because it has a lid, which makes transporting and storing leftovers super easy.
Want to skip slicing the cake in half? If you have two 9×13 metal pans, divide the batter evenly and bake the cakes separately instead of slicing one cake horizontally. It saves time and makes assembly much easier! Start checking for doneness around 24 minutes and add time as needed.
Piping tip. You don’t need a piping tip to make the swirls, but it definitely helps! I use a small round tip (like a Wilton #5 or #8) to pipe the squiggles across the cake width-wise. If you’re slicing the cake into 15 larger pieces, you’ll want 5 or 6 swirls across the top—adjust based on how many servings you want.
Vanilla extract. If you want a deeper vanilla flavor, use vanilla bean paste instead of extract. It gives the cake those little flecks of vanilla and a bakery-style finish. Not essential, but it’s a great upgrade if you have it.
Slicing clean layers. If you’re slicing the cake in half to fill it, chill it in the fridge for 30 minutes first. It firms up the crumb and makes it easier to get a clean, even cut.
HOW TO GET CLEAN SLICES
This is a question I get all the time so I wanted to write out exactly what I do to get these clean slices every time! After assembling and decorating the cake I chill completely for at least 1 hour. You can also pop this in the freeze for an hour as well but if it’s frozen solid it will be harder to cut! After chilling the cake, fill a large glass with hot water. I typically use a large Stanley or travel mug. Place a large, sharp knife (not serrated) in the hot water for 1 minute. Right before cutting pull the cake out of the fridge. Wipe the knife with a paper towel or towel and immediately slice. You do not want any water transferring to the cake. Repeat for each slice, allowing the knife to get hot again by placing in the water for 10-15 seconds and clean off any excess cake or filling. That’s how I get picture perfect slices every time 🙂
This Vanilla Hostess Sheet Cake is everything you love about the classic snack cake—fluffy vanilla layers, sweet marshmallow cream filling, and those signature white swirls on top. The filling is thick enough to hold its shape, easy to work with, and just sweet enough without being overpowering. It’s simple, nostalgic, and guaranteed to be a hit at your next gathering.
Vanilla Hostess Sheet Cake
Ingredients
For the cake:
- 1 box yellow cake mix 15.25 oz
- 1 cup all-purpose flour
- 1 cup granulated sugar
- 3 eggs room temperature
- 1 ¼ cups whole milk room temperature
- ½ cup sour cream room temperature
- ¼ cup vegetable oil
- 1 tsp vanilla extract
For the filling:
- ¾ cup unsalted butter
- 7 oz marshmallow cream
- 2 cups powdered sugar
- 1 tsp vanilla extract
- 2-3 tbsp heavy cream
- pinch of salt
Instructions
For the cake:
- Preheat oven to 325°F. Grease a 9×13-inch pan, line with parchment paper, and set aside. If using two pans, prepare two pans.
- In a large bowl, whisk together cake mix, flour, sugar, and salt. In another bowl, whisk together eggs, milk, sour cream, oil, and vanilla until smooth. Pour wet ingredients into dry and mix until just combined. Batter will be thick and creamy.
- Pour into the prepared pans and bake for 30-35 minutes in 1 pan or 25-28 minutes in two, or until a toothpick inserted in the center comes out clean. Let cool completely in the pans on a wire rack before frosting.
For the filling:
- Beat the butter until smooth and fluffy. Add marshmallow fluff and mix until combined. Slowly mix in powdered sugar, vanilla, and salt. Add cream or milk only if needed to smooth it out. You want it thick but spreadable—not runny.
For assembly:
- Once the cake is fully cooled, if you only used 1 pan carefully slice it in half horizontally using a long serrated knife. (Tip: chill the cake for 20–30 minutes first to make slicing easier.)
- Take out 1/4 cup of the filling and add to a piping bag fitted with a small round tip. Spread the rest of the marshmallow filling evenly over the bottom layer, then gently place the top half or second sheet cake on top.
- Pipe swirls across the top. Chill in the refrigerator for at least 30 minutes to make slicing easy! Store covered at room temperature for up to 2 days, or in the fridge for up to 5.
Have you made these into cupcakes? Can we use this recipe and follow the directions for the chocolate hostess cupcakes you made?