Key Lime Pie Cake (Dairy-Free Doctored Mix)

Okay…here goes nothing. I’m going to say it and then duck for cover. Ready? I love me a good boxed cake mix! There…phew. It’s out now and I feel a sense of relief. But truly, I have zero problems with cake mixes. They are fluffy, easy, and totally yummy. A few extra ingredients can take a standard run-of-the-mill cake mix and turn it into a phenomenal cake. And that’s exactly what I did with this dairy-free Key Lime Pie cake using a doctored mix.

Note: This post contains affiliate links to which I earn a small commission, but don’t worry there’s no extra cost to you! Thank you for supporting CAKED by Katie.

Doctored Cake Mix: Key Lime Pie Cake Inspiration

It was Saturday and I was tired. Like really tired. I had spent the previous night talking and laughing outside by the campfire and went to bed far later than what a responsible adult should but my soul needed that time of light-hearted connection.

My children, however, get up at 7 am sharp every single morning. Regardless of what time they go to bed the night before, their internal alarm clocks are as prompt as ever (insert me shaking my fist in the air.)

So after only a handful of hours of sleep and a pot of coffee, I was still tired. I knew what flavor of cake I wanted for Sunday Family Cake but had no desire to put forth a lot of effort…insert trusty cake mix!

How to Doctor Up A Dairy-Free Cake Mix

I always, and I mean always, keep a box or two of white cake mixes in my pantry. I don’t even hide them, no shame in my cake mix game. I grabbed a box and tossed it in my KitchenAid.

Cake mixes do tend to get a bit clumpy so I always recommend giving them a quick sift first or a minute or two in the mixer with the whisk attachment to break any of those clumps.

Now here’s where the magic happens. Don’t do what the box instructions tell you to do, grab some egg whites, jello, greek yogurt, vanilla extract, and vegetable oil. And literally, dump it all in the mixer. Mix, pour, and bake. Bam! Done! So grab that trusty cake mix (I know y’all have one) and I’ll show you how to turn it into a fabulously fast and fanciful Key Lime Pie cake.

If you love a good doctored cake mix recipe, I’ve got a few here for you to try:

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Key Lime Pie Cake (Dairy-Free Doctored Mix)

5 Stars 4 Stars 3 Stars 2 Stars 1 Star

5 from 7 reviews

  • Author: Katie
  • Total Time: 1 Hour 30 Minutes
  • Yield: 10 Slices 1x
  • Diet: Low Lactose


Fluffy dairy-free lime cake layers filled with sour key lime filling and covered with the most delicious white chocolate graham cracker crumb buttercream. An easy recipe using a doctored cake mix that makes the perfect spring and summer treat!



Lime Cake

  • 1 box (461 grams) white cake mix *can sub gluten-free cake mix

  • 1 (85 g. package) lime jello powder

  • ½ teaspoon fine sea salt

  • ¾ cup dairy-free milk, room temperature

  • ⅔ cup dairy-free yogurt or sour cream, room temperature

  • 4 large egg whites, room temperature

  • ⅓ cup vegetable oil

  • 1 tablespoon vanilla extract

  • 1 tablespoon key lime juice

Key Lime Filling

  • ⅛ cup granulated sugar *use ¼ cup if you prefer a sweeter filling

  • 2 tablespoons cornstarch

  • ¾ cup key lime juice

  • 1 tablespoon lemon juice

  • 1 tablespoon dairy-free salted butter

  • optional: green gel food color * I used ChefMaster

White Chocolate Graham Cracker Buttercream

  • 2 cups dairy-free salted butter, room temperature

  • 6 cups icing sugar

  • 1 cup dairy-free white chocolate chips

  • 1 cup dairy-free graham cracker crumbs *can sub gluten-free graham cracker crumbs

  • 1 tablespoon vanilla extract

  • 1 teaspoon fine sea salt

  • optional: pink gel food color * I used ChefMaster


Lime Cake

  1. Preheat oven to 350 degrees and prepare three 6-inch round cake pans with non-stick baking spray and parchment paper.

  2. In the bowl of a stand mixer give the cake mix, jello powder, and salt a quick whisk to break up any clumps.

  3. Add in all the wet ingredients and mix until combined. Be careful not to overmix.

  4. Divide batter between the prepared pans and bake for 20-25 minutes or until a toothpick comes out with a few crumbs.

  5. Cool in pans for 10 minutes and then invert on a cooling rack to fully cool.

Key Lime Filling

  1. In a medium pot combine sugar, cornstarch, and key lime juice and mix until smooth.

  2. Cook mixture on medium-low heat constantly stirring until mixture thickens and comes to a boil. Let boil for 1 minute and remove from heat.

  3. Add in the lemon juice, butter, and green food color (if using) and stir until melted and fully combined.

  4. Pour into a shallow dish and cover the surface directly with plastic wrap. Allow to cool fully.

White Chocolate Graham Cracker Buttercream

  1. In a small microwave-safe bowl melt the white chocolate chips in 30-second intervals until fully melted and smooth. Set aside.

  2. In the bowl of a stand mixer with the paddle attachment cream the butter on high speed until light and fluffy. Approximately 10 minutes.

  3. Add the icing sugar, graham cracker crumbs, salt, vanilla extract, and pink food color (if using) and mix on low until combined.

  4. While the mixer is on low, slowly pour in the melted white chocolate.

  5. Turn the mixer up to high and let mix for 5 minutes until smooth and creamy.

Cake Assembly

  1. Place one leveled layer of lime cake on a cake board or plate. Top with approximately 1 cup of buttercream.

  2. Pipe a border of buttercream around the edge and fill with approximately ⅓ cup key lime filling. Repeat with the remaining layers and apply a thin coat of buttercream all over the cake. Refrigerate for 20 minutes.

  3. Cover the cake with another layer of buttercream and smooth the sides.

  4. Decorate as you desire. I left the top edge raw and unfinished for a rustic aesthetic and used fresh key lime slices, graham crackers, and white chocolate chunks and shavings to decorate a top border. Enjoy.


  • substitute regular limes and lime juice if you cannot find key limes
  • Prep Time: 60 Minutes
  • Cook Time: 30 Minutes
  • Category: Cakes
  • Method: Baking
  • Cuisine: American


  • Serving Size: 1 Slice
  • Calories: 998
  • Sugar: 72 Grams
  • Sodium: 397 Miligrams
  • Fat: 60 Grams
  • Saturated Fat: 39 Grams
  • Unsaturated Fat: 14 Grams
  • Trans Fat: 5 Grams
  • Carbohydrates: 89 Grams
  • Fiber: 6 Grams
  • Protein: 8 Grams
  • Cholesterol: 221 Miligrams

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  1. If you are looking for a cake that tastes just like key lime pie, look no further! This cake is absolutely amazing. It’s as easy as pie to make (actually easier, pie for me it’s tricky lol). Everyone in the whole family enjoyed it, including my picky 6 year old who ate an adult size piece. And that buttercream! It’s heaven! I can eat that all day!

    1. Thank you for the glowing and heartfelt review, Mariela. I, too, could eat this buttercream by the spoonful. In fact, I did!

  2. This cake recipe was a crowd pleaser and was so moist and yummy! We are dairy eaters/lovers in this house, so I opted for all dairy products as well as added some lime zest to the cake and the buttercream. It was absolutely amazing and definitely a keeper! I would highly recommend giving this recipe a try, you won’t be disappointed!!!

  3. I made this cake at the request of my Mom for her birthday. Let me tell you, it did NOT disappoint. In fact, she said it was the “best cake she’s ever had.” Perfectly light and fluffy cake layers with a tangy lime filling and a decadent Graham cracker buttercream? You can’t go wrong. It was the perfect start to spring. Every person at the table enjoyed it. I have a feeling this cake will be a regular family request!

    1. You have made my day Kristi! I so appreciate you taking the time to bake this cake and let me know how it went. And a happy belated birthday to your mom.

  4. I’m surprised at how much this actually tasted like key lime pie. I’ll definitely make this one again.

    1. Right?! It’s sweet and tart and zesty just like a key lime pie. Thanks for giving it a shot April.

  5. Just ‘found’ you – Very talented!

    You must have so much fun and satisfaction creating these epic looking cakes!

    Well done

    1. Yay, I am so glad to have you here Sherri! I truly do have a lot of fun in the kitchen.

  6. My husband is a key lime everything fan and this recipe did not disappint. Plus it was really easy to follow with the cake mix.

    1. Thanks for giving this one a shot! I simply adore how easy it is to doctor up a cake mix.

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