This Lime & Coconut Cake evokes the very best of those tropical island flavors. Tender coconut lime cake layers with a tangy lime curd and silky coconut buttercream.
Preheat oven to 325F. Grease and flour three 8" cake rounds and line with parchment.
In a medium bowl, whisk flour, baking powder, and salt until well combined. Set aside.
Using a stand mixer fitted with a paddle attachment, cream butter and lime zest until smooth. Add sugar and beat on med-high until pale and fluffy (approx 3mins).
Reduce speed and add eggs one at a time fully incorporating after each addition. Add vanilla.
Alternate adding flour mixture with milk, beginning and ending with flour (3 additions of flour and 2 of milk). Fully incorporating after each addition. Gently fold in shredded coconut.
Spread batter evenly between the prepared pans and smooth the tops.
Bake for about 35mins or until a toothpick inserted into the center comes out mostly clean.
Place cakes on wire rack to cool for 10mins then turn out onto wire rack to cool completely.
Lime Curd:
Place eggs and sugar into a small pot, whisk to combine. Add lime juice and zest. Cook over medium-low heat whisking constantly until mixture thickens and coats the back of a spoon. Stir in cubed butter and whisk until smooth.
Transfer to a glass bowl and lay plastic wrap directly on surface to prevent a skin from forming. Chill for 2 hours to set. Makes a little over 1 cup.
Coconut Swiss Meringue Buttercream:
Place egg whites and sugar into the bowl of a stand mixer, whisk until combined.*
Place bowl over a pot with 1-2" of simmering water and whisk constantly until the mixture is hot and no longer grainy to the touch or reads 160F on a candy thermometer (approx. 3mins)
Place bowl on your stand mixer and whisk on med-high until the meringue is stiff and cooled (the bowl is no longer warm to the touch (approx. 5-10mins)).
Switch to paddle attachment. Slowly add cubed butter and mix until smooth.**
Add 6-8 Tbsp coconut milk powder (to taste) one Tbsp at a time whip until smooth.
Assembly:
Place one layer of cake on a cake stand or serving plate. Poke holes into the cake using a bamboo skewer. Brush with simple syrup if desired.
Spread a thin layer of buttercream on top of the layer and pipe a border around the outside to hold the lime curd in. Fill with about 1/2 cup of lime curd. Repeat with next layer.
Place final layer on top and do a thin crumb coat on the cake. Chill for 20mins.
Frost the top and sides of the cake with remaining frosting. Smooth the sides and top and do a rope border with the remaining buttercream. Fill the center with large toasted coconut chips and sprinkle with lime zest if desired.
Notes
* Ensure there is NO trace of egg yolks in your whites and that your mixer bowl and whisk is completely grease free or your meringue won't stiffen. ** The buttercream may look like it's curdled at some point. Keep mixing until it is completely smooth.