Easy and amazing key lime magic cake recipe, watch as this cake develops magical layers.
Key Lime Pie Magic Cake recipe being dusted with powdered sugar

I thought about making this Key Lime Pie Magic Cake recipe post in the style of Wordless Wednesday. For the past few days I’ve been completely stuffed, sneezing like crazy and if I rub my eyes any more, I swear they might pop out! It’s late and I want to go to bed. But I wanted to explain a little about my latest magic cake.

I just found out one of our neighbors in the street has a key lime tree. So far that makes our street an abundance of lemons, key limes, figs, oranges, peaches, grapes kumquats and plums. We could seriously start our own farmers market. She was kind enough to give me some key limes and of course the first thing I thought to make was key lime pie, right? But I haven’t made magic cake in a while and my mantra is, you can make anything into a magic cake. This is my fifth version of the layered cake which usually looks like it’s a positive fail when it goes in the oven but comes out with a cakey top and soft custard bottom layer.

Squares of Key Lime Pie Magic Cake recipe

I made a few adjustments to this original magic cake recipe from White On Rice Couple. I always follow a rule of mine whenever I begin to change a recipe, trying not to add more ingredients but adjust or switch out the ingredients already listed. Changing a liquid to another liquid or switching up seasonings. This way there’s less chance of the structure of the recipe failing. I tried to get as much key lime pie flavor into this recipe as I could, so for me that meant adding sweetened condensed milk and the key lime juice.

I was happy with the cake but be warned magic cakes aren’t particular sweet or gooey like brownies or blondies, but I love the texture and I could definitely taste the tartness of the key limes.

Key Lime Pie Magic Cake recipe will amaze your friends as it bakes

Key Lime Pie Magic Cake recipe

Check out my other Magic Cakes

Gingerbread Magic cake

Pumpkin Magic Cake

Chocolate Guinness Magic Cake

Pecan Pie Magic Cake

Key Lime Pie Magic Cake

Key Lime Pie Magic Cake

Prep Time: 15 minutes
Cook Time: 50 minutes
Print Recipe


  • 1/4 cup unsalted butter
  • 3/4 cup whole milk
  • 1 can sweetened condensed milk 14oz
  • 1/2 cup granulated sugar
  • 4 eggs separated
  • A few small drops of white vinegar
  • 1 1/4 cups powdered sugar
  • 1/2 cup fresh key lime juice
  • 1 cup all purpose flour
  • Extra powdered sugar for dusting the top of the cake


  • Preheat the oven to 325 degrees F. Grease an 8 x 8 brownie pan with butter.
  • Melt the butter and set aside.
  • In a small pot, combine the milk, condensed milk and granulated sugar until lukewarm.
  • Using a stand mixer, whip the egg whites and vinegar until stiff peaks form.
  • In a larger bowl, whisk the egg yolks and the confectioners sugar together until it turns a pale yellow color, about 3 minutes.
  • Add the melted butter and mix. Next add the lime juice and combine.
  • Add the milk mixture gradually whisking well each time.
  • Add the flour and mix well making sure there are no lumps.
  • Finally fold in the beaten egg whites in 3 stages making sure to get rid of most of the lumps but still try to keep it on the lighter side.
  • Once all of the egg whites have been mixed in, pour the batter into the prepared pan.until about an inch from the top.
  • Place in the upper part of the oven and bake for 50-55 minutes. The top should be still slightly wobbly when done but you'll see small cracks appear around the edges of the cake. It will continue to firm up as it cools down.
  • Dust heavily with extra powdered sugar before slicing and serving.


The cake is best served at room temperature and will slice better when completely cool. Store in the fridge if you're not going to use it for some time.
From White On Rice Couple, http://whiteonricecouple.com/recipes/magic-custard-cake/