Magnolia Cookie Cake

April 29, 2019

Magnolia Cookie Cake – Oatmeal chocolate chip cake layers with peanut butter frosting.

Happy Monday, friends! The weekend may be over, but the fun is just beginning. It’s the start of my birthday week and the day that I’m finally sharing my new cake, inspired by the Magnolia Cookie. Remember that cookie recipe I shared last week? The Copycat Magnolia Cookie, inspired by the oatmeal chocolate and peanut butter chip cookie from the Silos Bakery? So many of you have already whipped it up. I hope you loved it!

Well, now it’s time to bake the cake inspired by the cookie!

This cake is based off not only the Magnolia Cookie, but also my Oatmeal Chocolate Chip Cookie Cake. The cake layers are unlike any cake I’m guessing you’ve had. They’re hardy and chewy like a cookie… but not a cookie 😉

Just like the cookie I created, there’s a hint of cinnamon in the cake layers with mini chocolate chips in every bite.

I’ve also used my go-to peanut butter frosting. I love this frosting so much, I often just eat it by the spoonful! It’s so smooth and creamy, and the amount of peanut butter is just perfect. Of course, I always add a little heavy whipping cream to lighten up the texture.

It’s a simple cake, but one that definitely leaves an impression! Just look at those layers!


Magnolia Cookie Cake

5 from 13 votes
Oatmeal chocolate chip cake layers with whipped peanut butter frosting.
Servings 18 people
Prep Time 2 hours
Cook Time 40 minutes
Total Time 2 hours 40 minutes



  • 2 1/2 cups (591.5 g) water
  • 2 1/2 cups (225 g) uncooked old-fashioned oats divided
  • 1 cup (226 g) butter
  • 3/4 cup (150 g) granulated sugar
  • 1 cup (220 g) brown sugar packed
  • 2 teaspoons (8.4 g) vanilla
  • 4 eggs room temperature
  • 1 teaspoon (5.6 g) kosher salt
  • 2 teaspoon (8 g) baking soda
  • 2 teaspoon (5.28 g) cinnamon
  • 3 cups (360 g) all purpose flour
  • 1 cup (150 g) mini chocolate chips


  • 5 cups (625 g) powdered sugar measured and then sifted
  • 1 1/2 cups 3 sticks (339 g) unsalted butter, slightly cold
  • 1 cup (250 g) creamy peanut butter
  • 1 tablespoon (4.2 g) pure vanilla extract
  • 1/4 cup (57.75 g) heavy whipping cream
  • Pinch of coarse salt
  • *This buttercream recipe makes enough to fill and cover your cake. If you want to add additional piping, you’ll want to make an extra ½ batch.



  • Preheat your oven to 350 degrees F. Spray three 8-inch or four 6-inch round cake pans with nonstick cooking spray, line the bottoms with parchment paper and spray again. Set aside.
  • In a medium sized pot bring the water to a boil. Add in 2 cups of the oats, stir and remove the pot from the heat. Cover the pot and allow the oats to soak for 20 minutes, until all the water is absorbed. Let the oatmeal cool completely before adding it to the cake batter.
  • In a medium sized mixing bowl, combine the baking soda, salt, cinnamon, and flour. Whisk together. Set aside.
  • In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugars together on medium speed for 2 minutes until light and fluffy. Add in the vanilla and the eggs and mix until combined, scraping the sides of the bowl as necessary.
  • Turn the mixer to low and add in the cooled cooked oats and the flour mixture, mixing until just combined. 
  • Toss the mini chocolate chips in a tablespoon of flour and then stir into the batter, along with the remaining ½ cup dry oats.
  • Spread the cake batter into the prepared pans, about 20 ounces of batter in each 8-inch pan or 15 ounces in each 6-inch pan, and bake for 20-22 minutes or until the cake is set in the center and a toothpick comes out with just a few moist crumbs on it. 
  • Allow the cake to cool in the pans for about 5 minutes and then invert onto wire racks to cool completely. Level the cakes.
  • If you’re not using the cake layers right away, wrap each layer in plastic wrap. You can freeze them up to a week or up to a month if you also wrap them in foil.


  • In the bowl of electric mixer fitted with the paddle attachment, combine the butter and peanut butter. Beat on medium-high speed until smooth, about 2 minutes.
  • With the mixer on low speed, gradually add the powdered sugar, followed by the vanilla, salt and heavy cream.
  • Turn mixer to medium-high and beat the frosting for about 4 to 5 minutes.
  • Beat frosting by hand with a wooden spoon to get rid of air pockets.


  • On a cake board, spread a small dollop of frosting to hold the cake in place. Place your first of the three cake layers on the board, crumb side up.
  • Spread 1 cup of frosting (with chocolate chips) on the cake layer. Get eye level with the cake to make sure the layer of frosting is applied evenly.
  • Repeat step 2 for the next cake layer and layer of frosting. For the final cake layer, place it top side down, so the smoothest side of the cake (the bottom) is facing up.
  • Cover the entire cake with a thin layer of frosting. Chill the cake for 10 minutes to set the crumb coat and lock in the crumbs. 
  • Once the crumb coat is set, frost the cake with the remaining frosting.
Author: Courtney Rich
Course: Dessert
Cuisine: Cake

Join the Conversation

  1. Could you please explain the texture? Is it soft like cake or more cookie-like (chewy, crisp)?
    Thank you!

    1. Crispy on the outside and chewy on the inside

  2. When you say the butter for the icing has to be slightly cold, should it still be soft as well?

    1. Doesn’t have to be too soft. Just enough to make a fingerprint in it. Still cold to the touch

  3. Have you ever made this recipe into cupcakes?

    1. I haven’t yet, but it should work great. Just cook a little less.

  4. 5 stars
    I finally made this cake (saw it three weeks ago and finally had an event to make cake for!!) and since it was a pot luck I did it as a sheet cake! It worked our perfectly!!! It baked for about 15-18 minutes instead of 20+, and it cooled super fast so I could rustically Frost the top!🤪
    I actually didn’t have oats so I skipped the oats and water step and I added some chopped pecans with the chocolate chips for some extra crunch and flavor and everyone loved it!! I made it gluten free (with Bob’s Red Mill 1-1 baking flour) since my mom is allergic to wheat and nobody could even tell! 🙌🏼 (Which is a good sign because if the non gluten free eaters can tell… something is wrong!)
    Cake was more dense like cookies but still had a lighter texture that reminded you it was cake. It isn’t too sweet in my opinion, and I used semi sweet chocolate chips just in case it would have been.
    And I love these buttercream recipes, I will never make buttercream the same again!! Mine was always too stiff and thick and this is light and fluffy and delicious! I love it! Courtney is definitely my go to for buttercream now!! I even shared her recipe with my cousin who is far ahead of me in the homemade baker department, and she tried it and said she’ll never go back either!

  5. Jo Galpin says:

    Am making this for myself for my birthday cake this week. I’m in the UK, please can you convert the butter in the frosting to a weight (either grams or oz)? I don’t know what a stick is. Here, butter comes in 250g blocks… Thanks!

    1. 227 grams is one cup of butter. My frosting recipes mostly use two cups of butter.

  6. Can this be baked in a rectangular pan? If so, what size and how long do you recommend?

    1. Yes – 9″x13″ at 325 for about 40-45 minutes.

  7. Debbie despain says:

    5 stars
    Legit THE best tasting cake I’ve ever made and one of the best I’ve ever tasted!! I made it in a 9×13 and so made half the frosting and it was so amazing, such an interesting chewy texture I can’t even explain, I ate like half of it!!

  8. Was this supposed to be quick oats and not old fashioned?

    1. Old fashioned is preferred 🙂

  9. 5 stars
    This cake is DELICIOUS, seriously there is so much flavor. Normally I don’t think of the cake as the “star;” I prefer a nice filling or buttercream for the flavor, but this cake tastes amazing. The batter makes a sturdy, hearty cake, almost like a pound cake or a muffin, but it’s still very moist. It’s not normally the texture I go for with a cake, but given that this cake has oatmeal and chocolate chips in the batter, it’s the perfect texture.

    I made 3 x 6-inch cakes and followed the weight recommendation and the remaining batter was the perfect amount for 1 dozen cupcakes. I ate a cupcake straight out of the oven and it was heavenly.

    The only issue I had was the baking time (I have an oven thermometer so the temperature was correct). Mine was still raw in the center at 22 minutes; it was more like 25-27 minutes for a metal cake tester to come out with moist crumbs.

    1. Yes every oven is different! Glad you found the time that worked for you.

  10. 5 stars
    My favorite cake in the history of ever!

  11. My favorite cake in the history of ever!

  12. Could this be made as a 13×9 cake or divided into 8×8 cakes?

  13. Hi. How do you think this would work as a bundt cake? Could it possibly be too dense? Deciding between bundt and sheet cake if I don’t do the layers. Thanks!

  14. 4 stars
    I’ve made this cake twice now. It’s very moreish.
    I think it could use a pinch more salt, especially if you use unsalted butter in it. It’s dense, moist and exactly what you’d expect from an oatmeal cake. I’m going to make it again. Thank you for the recipe.
    I didn’t use the chocolate chips in it, opting for a chocolate ganache frosting instead.

  15. Help! I can’t see the recipe! I was looking at the recipe not that long ago and now I want to make it and the recipe is not showing up??? It just shows the description and cake and comments. No recipe

    1. Just a little site update and glitch. Getting it back up now!

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