Instructions

LIME CAKE

1. Adjust an oven rack to the center position and heat oven to 350 degrees. Spray 3 8-inch round cake pans with nonstick baking spray and set aside.
2. In a bowl or a 4 cup liquid measuring cup, whisk together milk, egg whites and lime flavoring. In the bowl of a stand mixer, with the paddle attachment attached, mix the flour, sugar, baking powder, salt and lime zest on low speed until combined. Add butter one tablespoon at a time until the mixture forms pea-sized pieces, about 1 minute. Reserve ½ cup of the milk mixture and pour the remaining to the flour mixture and mix on medium-high speed until light and fluffy, about 1 minute. Reduce the mixer speed to medium-low and add the reserved ½ cup milk mixture to the batter and mix until combined, about 30 seconds. Do not over mix. The batter may look curdled. Give the batter a final stir by hand with a rubber spatula.
3. Divide the batter evenly between the prepared cake pans and smooth tops with a rubber spatula. Gently tap cake pans on the counter to settle the batter and bake until a toothpick inserted in the centers comes out with a few moist crumbs attached, about 20 to 25 minutes, switching and rotating pans halfway through baking.
4. Let cakes cook in their pans on wire racks for 10 minutes. Invert cakes on to wire racks to cool completely, about 2 hours.
   

LIME CURD

1. In a medium sized saucepan, whisk together the eggs, sugar, salt, lime juice and zest.
2. Over low heat, whisk constantly for about 15 to 20 minutes or until the mixture starts to thicken. The curd should coat the back of a wooden spoon without being translucent.
3. Remove the curd from the heat and stir in the butter. Strain the curd through a fine-mesh sieve into a bowl to remove any solids that may have formed while cooking. Place a piece of plastic wrap on the surface of the curd and chill in the refrigerator for at least 3 hours or overnight.
   

COCONUT RUM SWISS MERINGUE BUTTERCREAM

1. In the bowl of a stand mixer fitted with the whisk attachment, pour in the egg whites and sugar and whisk by hand until combined. Fill a medium saucepan with about 2 inches of water and bring to a simmer. Place mixer bowl on top, being sure the bottom of the bowl does not touch the water and attach a candy thermometer.
2. Whisking occasionally, heat the egg mixture until the temperature reaches 160 degrees. Once the mixture reaches 160 degrees, transfer to a stand mixer and beat the mixture on high speed for 10 minutes or until medium-stiff peaks form. At this point the outside of the mixer bowl should be room temperature. Switch out the whisk attachment with the paddle attachment and with the mixer on low speed, add the butter one tablespoon at a time, and then add the vanilla extract, rum and coconut emulsion. Once combined, turn the mixer speed to medium-high and beat until buttercream is smooth, about 4 minutes. Reduce the mixer speed to low and beat for 1 more minute to remove as many air bubbles from the buttercream as possible.

ASSEMBLE

1. Place an 8-inch round cake board on a cake turntable and center the first layer of cake on the cake board. Fit a piping bag with a round piping tip or coupler and fill with about 1 1/2 cups buttercream. Pipe a buttercream dam around the edge of the cake. Spread half of the lime curd in the center and using a small offset spatula, spread out in an even layer until the filling reaches the buttercream dam.
2. Place the second cake layer on top and gently press down to adhere. Pipe a buttercream dam around the edge of the cake and place the remaining lime curd on the center of the cake and spread out in an even layer with your offset spatula.
3. Place the last cake layer on top (bottom side up). Add about 1 cup of buttercream spread a thin layer of buttercream over the entire cake creating a crumb coat. Chill the crumb coated cake in the refrigerator for 30 minutes.
4. If you’re using an acrylic disc, line one side with parchment paper using a small amount of buttercream to attach it. Apply a large amount of buttercream on the top of the cake and spread out evenly to the edge of the cake. You should have access buttercream hanging off the edge of the cake. Gently press the acrylic disc down on top. Make sure the disc and the bottom cake board line up and that the top of the cake is level.
5. Fit a piping bag with a round piping tip or coupler and fill with green tinted buttercream. Starting from the bottom of the cake, pipe buttercream around the bottom edge. Do this about three or for times around. The green buttercream should come up about halfway from the cake. Fit another piping bag with another round piping tip or coupler and fill with uncolored buttercream. Pipe buttercream around the cake starting from the green buttercream and working all the way up cover the entire side of the cake.
6. Gently press the cake scraper on the bottom cake board and the top acrylic disc and rotate the turntable to smooth out the buttercream. You may need to do this 2 to 3 times. Be sure to clean your cake scraper with every rotation. Fill in any gaps in with the appropriate color buttercream and smooth over again. Chill the cake in the refrigerator for 30 minutes.
7. With an offset cake spatula, gently remove the acrylic disc and fill in any spaces on the top with more buttercream and carefully smooth the top of the cake and edges, cleaning the cake spatula with every swipe.
8. Fit a piping bag with Wilton piping tip 1M and fill with both colors of remaining buttercream. Pipe some swirls around the edge of the cake. Place lime slices between each swirl and fill the center with coconut flakes and serve.