Instructions

1. To make Lime Rum Curd, in a large bowl, whisk egg yolks and cornstarch until well combined. Set aside.
2. Cut butter into cubes and set aside.
3. In a shallow sauté pan or large saucepan over medium heat, combine lime zest and juice, rum and sugar and whisk continuously until mixture starts to simmer.
4. Still whisking continuously, very slowly pour about three-quarters of lime mixture into egg mixture. Pour now-tempered egg mixture back into sauté pan with remaining lime mixture and set over low to medium-low heat. Cook, whisking continuously, until mixture thickens and reaches 180 F (82 C) on a digital thermometer, about 5 minutes. Take care, as mixture can curdle easily if heat is too high or you stop whisking. Once mixture has reached desired temperature, remove pan from heat and immediately whisk in cubed butter, 1 cube at a time, making sure each piece is fully melted and incorporated before adding next piece. Pour curd into a heatproof jar or bowl and cover with plastic wrap or parchment so that it is touching surface of curd. This will prevent a skin from forming on top of curd. Refrigerate while making cake, or for up to 1 week.
5. To make Spiced Gingerbread Cakes, preheat oven to 350 F (175 C). Grease two 6-in (15 cm) round cake pans and line with parchment. Set aside.
6. In a small saucepan over medium heat, melt butter, stirring occasionally. Add cream and milk and bring mixture to a hard simmer, stirring constantly. Remove saucepan from heat and set aside.
7. In bowl of a stand mixer fitted with paddle attachment, combine eggs and brown sugar. Beat on medium speed until pale, about 4 minutes. Add honey and fresh grated ginger and mix until well incorporated.
8. Into a large bowl, sift flour, baking soda, spices and salt. Add a third of flour mixture to egg mixture and incorporate on low speed until smooth. Add a third of butter mixture and mix in at low speed. Continue alternating between adding dry and wet ingredients to batter while mixing on low speed until well incorporated, taking care not to overbeat.
9. Divide batter evenly among prepared cake pans, making sure tops sit level. Bake in preheated oven until a cake tester comes out clean, 40 to 50 minutes. Let cakes cool in pans for 15 minutes before turning out onto a rack and letting cool completely at room temperature. Cakes can be stored in an airtight container in refrigerator for up to 4 days.
10. While cakes cool, make White Chocolate Cream Cheese Frosting. Place chopped chocolate in a heatproof bowl and melt in microwave in 15-second bursts, stirring in between, until chocolate is mostly melted. Stir without further heating until chocolate is completely melted. Let cool until just slightly warm to touch, 80 to 85 F (27 to 29 C) on a digital thermometer.
11. In bowl of a food processor fitted with S blade, combine cream cheese, butter and sour cream. Process, scraping down sides of bowl as needed, until smooth and creamy. Add cooled, melted white chocolate and pulse several times to incorporate. Add vanilla and pulse until incorporated. Can be stored in an airtight container in refrigerator for up to 1 week. Let frosting come to room temperature before using so that it is easier to work with.
12. When ready to assemble, level each cake by slicing off cake domes, then cut each cake in half lengthwise to yield 4 cake layers. Use 1 base layer for bottom of cake and second base layer, unsliced side up, for top of cake to avoid crumbs in frosting. Place first cake layer on a cake stand or plate and spread a thin layer of frosting on top, smoothing it with a palette knife. Place one-third of frosting in a piping bag fitted with a large plain round tip. Pipe a frosting dam around edge of cake layer, then use a spoon to fill with an even layer of lime rum curd. The frosting dam should stop any curd from escaping out sides of cake. Place second cake layer on top and repeat steps to pipe frosting and spread lime rum curd, then add third cake layer and repeat again. After adding final cake layer, cover top and sides of cake with a very thin layer of frosting and smooth with a palette knife, allowing portions of cake to remain visible and creating a semi-naked cake appearance. Finish decorating as desired. Place cake in refrigerator for about 30 minutes to allow frosting to firm up a bit and set cake layers together.
13. To serve, slice cake with a clean, sharp knife that has been warmed under hot water. Wipe blade clean after each slice.