Oatmeal cream pie cake takes everything you loved about that classic Little Debbie snack and turns it into a real, homemade layer cake. The soft oatmeal cake layers have a hint of cinnamon and molasses. The two layers then sandwich a marshmallow cream filling that tastes like the real thing. It looks impressive, but is simple to put together. One bowl for the cake batter, a little time for the cake layers to cool and a super easy marshmallow cream filling. No complicated techniques or decorating, just a beautiful homemade nostalgic cake.
Disclosure | This post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.
Jump to:
I went back and forth on this one. Do I just bake two giant oatmeal cookies and call it a cake? It was tempting! But I really wanted that soft, tender cake texture you expect when you slice into a real layer cake. So I looked to the Quaker Oats lazy daisy cake and old fashioned oatmeal cake recipes for inspiration. The result is a denser cake (in a really good way!) with a wonderful chewiness from the rolled oats and a hint of cinnamon. Your inner child is going to be really happy with this one!
If you love this kind of nostalgic baking, my brown sugar snack cake bars have the same cozy, old fashioned feel. You might want to add them to your baking list!
💗 why you will love this nostalgic cake flavor
This cake checks all the boxes for those of us that want something homemade, but don’t want an all day project! Here’s why it works so well:
- Melted butter means no waiting for butter to soften!
- One bowl cake batter that comes together quickly.
- The old fashioned rolled oats soak in water first, creating a super tender and slightly chewy crumb.
- A hint of cinnamon and molasses give that classic oatmeal cookie flavor.
- The marshmallow cream filling is fluffy, sweet and easy to make. The same one we use in oatmeal cream pie cookies.
- No frosting on the cake or fancy decorating, just a dusting of confectioners’ sugar and you are done!
🛒 ingredient notes
As someone who has been baking for decades and has several nostalgic cake flavors under my belt (peanut butter and jelly cake, cereal cake, and orange creamsicle), I tested this recipe several times to get it right. I tried more molasses and a hint of nutmeg, but it tasted more like a spice cake and less like an oatmeal cookie. Once I dialed it back to one teaspoon of molasses, eliminated the nutmeg and let the oats do their thing, the flavor was spot on. Tender, a little chewy, and so familiar.
Please scroll to the printable recipe card at the end of this post for the full list of ingredients and baking directions.
Old fashioned rolled oats ~ they are key to the cake! They take a soak in hot water to soften them before adding to the cake batter.
Molasses ~ just a teaspoon! One teaspoon is enough to add subtle richness and deepen the color without taking over. I use Wholesome unsulphered molasses.
Brown sugar ~ I prefer dark brown sugar for the best flavor, but light brown works just fine too.
Marshmallow fluff ~ one full 7-ounce container goes into the filling. This is what gives the cream pie middle the signature fluffy, sticky sweetness.
🥣 how to make in photos
Melt the butter and set aside in a medium to large bowl to cool for 15 minutes.
Place the old fashioned rolled oats in a bowl and pour the hot water over. Allow to soak for 15 minutes.
Preheat the oven to 350°F and prepare two 8-inch round baking pans by buttering and lining the bottom with a parchment paper round.
Add the granulated sugar, brown sugar, kosher salt, eggs, vanilla, and molasses to the cooled melted butter. Whisk together until completely combined.
Then add the cinnamon and baking soda and whisk until combined.
Now add the soaked rolled oats with a spatula, mixing until combined. Then add the flour and mix until the cake batter comes together.
Divide the oatmeal cake batter into the prepared pans. Use an offset spatula to smooth, if needed.
Bake in the preheated oven for 25-30 minutes or until a toothpick inserted in the center comes out clean or with just a few moist crumbs.
Allow the cake to cool in the pans for 10 minutes. Then remove to a wire cooling rack to cool completely (about 2 hours at room temperature).
🤍 how to make the marshmallow cream pie filling
Using a stand mixer with the paddle attachment or a hand mixer, combine the room temperature butter and a pinch of kosher salt on medium-high for 2 minutes. Scrape up and down the bowl and add the confectioners' sugar and vanilla and beat on low until the sugar is combined, then increase the speed to high and beat until light and fluffy.
Then scrape up and down the bowl and add the marshmallow fluff and beat on medium another minute until combined and fluffy.
(My marshmallow frosting was a little soft here. If yours looks this soft, pop it in the refrigerator for about 10 minutes).
To assemble the cake, place a cooled cake layer on a cake stand or plate with the flat side down. Spoon marshmallow cream filling over the cake and use an off-set spatula to evenly spread it over the cake. Then place the second cake layer on top with the flat side facing up.
Dust with confectioners' sugar, if desired. Then slice and serve.
💬 frequently asked questions
can I use quick oats instead of old fashioned rolled oats?
I only tested this recipe with old fashioned oats. Quick oats absorb the water differently and may change the texture of the cake. But I will tell you that the Quaker Oats lazy daisy cake says you can use either. If you try them, let me know how it goes.
why is my marshmallow filling so soft?
This can happen if the butter is too warm or you make the filling on a warm day. Just place the filling in the refrigerator for about 10 minutes and it will firm up.
👩🏻🍳 tips for the best oatmeal dessert cake
Do not skip the oat soak. 15 minutes in hot water helps is what makes this cake tender and chewy.
Use a scale to measure your ingredients. I know I say this all the time, but it really will make you a better baker. Too much flour and the cake will be dry. Weighing ingredients is the most accurate. I use this OXO scale, but this Escali scale is a great economical option.
Cool the cake completely before filling. If the cake is too warm, the filling will slide right out.
The tops of the cakes may bake a little unevenly. This is okay! The two flat sides of the cakes will be the top and bottom when finished, so it all evens out beautifully.
Remember to snap a picture and tag me on Instagram if you make this Easy Oatmeal Cream Pie Cake. It warms my heart to see you bring these recipes to life! Thank you for being here and happy baking!
If you make this recipe {or any recipe!} from two sugar bugs please come back and leave a review and a ⭐️⭐️⭐️⭐️⭐️ star rating. I read every comment, and I LOVE hearing from you!
📖 recipe
Easy Oatmeal Cream Pie Cake
recipe created and tested by:
I highly recommend using weight (metric) measurements when available for more accuracy and the best results.
Please note
When using 2x or 3x ingredients, the grams DO NOT adjust, you will have to manually do that.
Ingredients
oatmeal cake
- ½ cup unsalted butter melted and cooled, 113g
- 1 cup old fashioned rolled oats 80g
- 1 ¼ cups hot water 296mL
- ¾ cup granulated sugar 150g
- ¾ cup brown sugar packed 150g
- ½ teaspoon kosher salt
- 2 large eggs
- 1 teaspoon pure vanilla extract
- 1 teaspoon molasses 6g
- 1 teaspoon cinnamon
- 1 teaspoon baking soda
- 1 ⅓ cups all-purpose flour 167g
cream pie filling
- ½ cup unsalted butter room temperature 113g
- 1 cup confectioners' sugar 120g
- 1 teaspoon vanilla
- 7 ounces marshmallow fluff 198g
Instructions
- Melt the butter (½ cup/113g) and set aside in a medium to large bowl to cool for 15 minutes.
- Place the old fashioned rolled oats (1 cup/80g) in a bowl and pour the hot water (1 ¼ cups/296mL) over. Allow to soak for 15 minutes.
- Preheat the oven to 350°F and prepare two 8-inch round baking pans by buttering and lining the bottom with a parchment paper round.
- Add the granulated sugar (¾ cup/150g), brown sugar (¾ cup/150g), kosher salt (½ teaspoon), eggs (2 large), vanilla (1 teaspoon), and molasses (1 teaspoon/6g) to the cooled melted butter. Whisk together until completely combined, about 1 minute.
- Then add the cinnamon (1 teaspoon) and baking soda (1 teaspoon) and whisk until combined, about 30 seconds.
- Now add the soaked rolled oats with a spatula, mixing until combined. Then add the flour (1 ⅓ cups/167g) and mix until the cake batter comes together.
- Divide the oatmeal cake batter into the prepared pans (I got between 500-507g of batter per pan). Use an offset spatula to smooth, if needed.
- Bake in the preheated oven for 25-30 minutes, until a toothpick inserted in the center comes out clean or with just a few moist crumbs.
- Allow the cake to cool in the pans for 10 minutes. Then remove to a wire cooling rack to cool completely (about 2 hours at room temperature).
- Once the cake is cool, make the cream pie filling.
for the marshmallow cream pie filling
- Using a stand mixer with the paddle attachment or a hand mixer, combine the room temperature butter (½ cup/113g) and a pinch of kosher salt on medium-high for 2 minutes. Scrape up and down the bowl and add the confectioners' sugar (1 cup/120g) and vanilla (1 teaspoon) and beat on low until the sugar is combined, then increase the speed to high (speed 8 on KitchenAid) and beat until light and fluffy, about 2-3 minutes. Then scrape up and down the bowl again and add the marshmallow fluff (7 ounces/198g) and beat on medium another minute until combined and fluffy.
- If the marshmallow frosting seems too soft, place in the refrigerator for 10 minutes before filling the cake. (mine was a little soft in these photos and would have benefited from a short sit in the refirgerator!)
to assemble the cake
- Place a cooled cake layer on a cake stand or plate with the flat side down. Spoon marshmallow cream pie filling over the cake and use an off-set spatula to evenly spread it over the cake. Then place the second cake layer on top with the flat side facing up.
- Dust with confectioners' sugar, if desired. Then slice and serve.
Notes
Nutrition
The nutrition information is based on third-party calculations, is an estimate only and may not be entirely accurate. Actual nutritional values will vary based on brands used and portion sizes.
Please take a moment to leave a comment, review or ask a question.