Triple Coconut Cupcakes filled with a Rum-Infused Coconut Custard

When I find a recipe that I want to make, my general rule of thumb is to follow the recipe exactly the first time. Then, I usually think about what I liked and didn’t like and ways to perfect the recipe.  
 
The coconut cake recipe below is by Rose Levy Beranbaum, who is the ultimate cake guru. And that's not just my opinion, that's a fact.  I have never found one of her cake recipes that wasn’t perfect. What I like most about Rose’s recipes is that she uses the “reverse creaming method” for most, if not all of her cakes. In the reverse-creaming method, you mix all the dry ingredients and the sugar together first.  Next you mix the fats (e.g., butter) and a portion of the liquids into the dry ingredients followed by the remaining liquids. For me, this method is so easy and produces a perfect cake crumb every time. 
 
The first time I made a coconut cupcake, I used Rose’s heavenly coconut seduction cake recipe and frosted the cupcakes with a coconut Italian meringue buttercream.  In my opinion, while the cake part of the cupcake was perfect, the overall taste of the cupcake and frosting left me wanting —the coconut flavor was just so underwhelming. So I started thinking about how I could jazz it up. Then it hit me like a ton a bricks — the answer was simple — I could fill the cupcakes with a rum-infused coconut custard. 
 
These cupcakes are sweet, moist, and luscious. The tender crumb of the cupcake is loaded with a triple blast of coconut flavor  - shredded unsweetened coconut, cream of coconut, and coconut extract. They are filled with a rum-infused coconut custard and then topped with a tropical coconut buttercream and finished off with a nice nutty crunch of shredded toasted sweetened coconut. These are not your ordinary run-of-the-mill coconut cupcakes. It is the ultimate coconut cupcake.  
 
Coconut cake recipe adapted from Rose Levy Beranbaum, Rose's Heavenly Cakes 
Rum-infused coconut custard recipe adapted from Dorie Greenspan's Baking: From My Home to Yours 
 
 
Makes 12 cupcakes
 



 

Ingredients

 

For the cupcakes:

  • 3 large egg whites, room temperature
  • 2/3 cup canned cream of coconut, divided (processed in food processor before measuring)
  • 3/4 teaspoon pure vanilla extract
  • 3/4 teaspoon coconut extract
  • 1/2 cup minus 1 tablespoon superfine sugar 
  • 1/2 cup desiccated unsweetened grated coconut
  • 2 cups cake flour, sifted into the cup and leveled off 
  • 2-1/4 teaspoons baking powder
  • 1/2 teaspoon salt
  • 8 tablespoons unsalted butter (1 stick)

 

For the rum-infused coconut custard:

  • 2 cups whole milk
  • 1/2 cup sugar
  • 6 large egg yolks
  • 1/3 cup cornstarch, sifted
  • 2 tablespoons dark rum
  • 1 teaspoon vanilla extract
  • 3-1/2 tablespoons cold unsalted butter, cut in small pieces
  • 1/2 cup shredded sweetened coconut

 

For the coconut buttercream:

  • 1 cup unsalted butter, at room temperature
  • 3-1/2 cups powdered sugar
  • pinch of sea salt
  • 1/4 cup heavy cream
  • 2 teaspoons coconut extract
  • 1/2 cup of cream of coconut
  • Lightly toasted coconut for adding to the top of the buttercream
 



 

Instructions

 
Step 1: To make the cupcakes: Preheat the oven to 350°F.  Line 12 cupcake tins with cupcake papers
 
Step 2: In a medium bowl whisk the egg whites, 3 tablespoons of the cream of coconut, the vanilla, and the coconut extract just until lightly combined.
 
Step 3: In a food processor, process the sugar and coconut until the coconut is powder fine.
 
Step 4: In the bowl of a stand mixer fitted with the flat beater, mix the coconut-sugar mixture, flour, baking powder, and salt on low speed for 30 seconds. Add the butter and remaining cream of coconut. Mix on low speed until the dry ingredients are moistened. Raise the speed to medium and beat for 1-1/2 minutes. Scrape down the sides. 
 
Step 5: Starting on medium-low speed, gradually add the egg white mixture in two batches, beating for 30 seconds after each addition to incorporate the ingredients and strengthen the structure. Scrape the batter into the prepared pan, and smooth the surface evenly.
 
Step 6: Divide batter evenly among lined cups, filling each about three quarters full. Bake for about 20- 25 minutes (the tops should spring back from a gentle touch.) When done, transfer tins to wire racks to cool 10 minutes; turn out cupcakes onto racks and let cool completely.
 
Step 7: Toast coconut at 350 degrees until lightly toasted.  
 
Step 8: To make the custard: Bring the milk to a soft boil. 
 
Step 9: In a large saucepan whisk together the sugar, egg yolks, cornstarch and salt until well combined. While constantly whisking, pour 1/4 of the milk into the egg mixture. Continuing to whisk, slowly pour the remaining milk into the eggs. While still whisking, heat the mixture over medium heat until it begins to boil; let boil for up to 2 minutes, until it thickens. 
 
Step 10: Mix in the rum and vanilla. Let it stand for 5 minutes. Then add the bits of butter. This should make the custard very smooth. Stir in the coconut. Cover with plastic wrap pressed against the custard and cool in the refrigerator for at least 20 minutes. You can also store the custard overnight until ready to use.
 
Step 11: To make the coconut buttercream: In the bowl of a stand mixer fitted with a paddle attachment, whip butter on medium-high speed until very fluffy, about 8 minutes, occasionally scraping down the sides and bottom of the bowl. Add powdered sugar and salt, and beat on low to incorporate.
 
Step 12: Add heavy cream, coconut extract, and cream of coconut, mixing on low until combined. Increase mixer speed to high and beat until very light and fluffy, about 5 to 6 minutes, occasionally scraping down the sides and bottom of the bowl.
 
Step 13: To assemble the cupcakes: Remove the middle of the cupcake using a cupcake corer. Fill the center with the coconut custard filling. Top with coconut buttercream and sprinkle with toasted shredded coconut.