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Key Lime Rum Cake is an easy make-ahead dessert that is tart, tasty, and ideal for entertaining.
As you know, this time last week I was still sailing the high seas on my way back from the last port in our cruise. (Sigh!) One of the reasons we booked this cruise is that it started with a stop in Key West. I love Key West but I hate driving there so anytime I find a cruise itinerary that includes a stop to the Florida port I highlight it for future reference!

Key West is known for many things like its sunsets, Hemingway, and that it’s the southernmost point in the continental United States. However, there is one thing that most people think of immediately when they think of Key West and that is Key Lime Pie!

Its sweet and tart filling inside a crumbly graham cracker crust is so light and refreshing and the ideal dessert on a warm Florida evening. The Florida Keys once dominated the market in producing the tart key lime thanks to its local terrain. Unfortunately, key limes are no longer commercially produced in Florida but that doesn’t keep the local vendors from churning out delicious pies!

I was inspired by our recent trip to Key West to come up with another tropical dessert using delicious key lime juice. You may remember the Bacardi Rum Cake recipe I shared with you this past September. This time I took inspiration from King Arthur Flour’s mostly homemade version. I just did a little tweaking to include cake flour and of course, the key lime juice.
The result was a beautiful and moist rum cake with just enough tangy lime flavor to tease your palate! I hope you enjoy this Key Lime Rum Cake as much as we do. It will be a wonderful dessert to add to your spring and summer menus especially when you’re entertaining!
If you know of anyone who would love this rum cake, please share this post with all your friends and family. Just click on the social media icons below! Have a wonderful weekend and enjoy!
Key Lime Rum Cake
Ingredients
Cake
- 2 ½ cups cake flour
- 1 cup granulated sugar
- ½ cup brown sugar
- 1 box instant vanilla pudding 3.75 oz package
- 2 tsp baking powder
- 1 tsp salt
- ½ cup unsalted butter softened
- ½ cup canola or vegetable oil
- ½ cup whole milk
- 4 eggs
- ½ cup Bacardi Silver Rum
- ½ cup Key Lime Juice
- 2 tsp vanilla extract
- Confectioner’s sugar optional garnish
Key Lime Syrup
- ½ cup butter
- ¼ cup Key Lime Juice
- 1 cup granulated sugar
- ½ cup Bacardi Silver Rum
Instructions
Cake
- Preheat oven to 325°. Grease and flour 10” tube or 12-cup bundt pan.
- In a large mixing bowl, add the cake flour, both sugars, pudding mix, baking powder, salt, butter, and oil. Mix at medium speed with an electric mixer until everything is combined and with a sandy texture.
- Beat in the milk. Follow with the eggs, one at a time.
- Stir in the rum, key lime juice, and vanilla extract.
- Pour the batter into the prepared pan and bake for 50 – 60 minutes or until baked through and a cake tester comes out clean when inserted.
- Remove the cake from the oven and let cool slightly while you prepare the key lime syrup.
- With the cake still in the pan, use a long skewer to poke holes all over the bottom of the cake. Pour about a ¼ cup of the syrup over the cake. Allow it to soak in and repeat it again as needed until all the syrup is used.
- Loosely cover the pan with plastic wrap and allow the cake to cool completely and absorb all the syrup by sitting at room temp overnight.
- Loosen the edges of the cake before inverting onto the serving plate. Garnish the cake, if desired, by lightly dusting it with confectioner’s sugar and key lime slices.
Key Lime Syrup
- Melt butter in a saucepan. Stir in juice and sugar. Boil for 5 minutes, stirring constantly. Remove from heat. Stir in rum.
Notes
***You can use fresh or bottles key lime juice. Key Limes weren’t in season when I made this cake, so I used Nellie & Joe’s Key West Lime Juice.***
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