THE Coconut Cake - Prepare from Scratch

      Prepare the cake layers: Preheat the oven to 350°F (180°C) with the rack positioned in the center. Apply baking spray with flour to 3 round cake pans (8 inches/20cm). Line the bottoms of the pans with parchment paper and lightly spray the paper as well. In a medium bowl, sift together the flour, baking powder, and salt. In a large liquid measuring cup with a pour spout, whisk together the buttermilk, melted butter, oil, vanilla, and coconut extract.

      In the metal bowl of a stand mixer (or a medium heat-safe mixing bowl), whisk the eggs and sugar together until well combined. Place the bowl over a medium saucepan of water that is barely simmering, ensuring the bottom of the bowl does not touch the water. Heat the mixture while constantly whisking until it reaches 105°F (40°C).

      Remove the bowl from the double boiler and transfer it to the electric mixer fitted with the whisk attachment. If using a hand mixer, continue in the same bowl. Beat the eggs on high speed until they are pale and thick, about 5 to 6 minutes. Lower the speed to medium and whisk for an additional 2 to 3 minutes. Sprinkle about one-quarter of the flour mixture over the egg mixture and mix on low speed until just combined. Add the remaining flour mixture in 2 to 3 additions, mixing just until incorporated.

      With the mixer on low speed, gradually pour in the buttermilk mixture in a steady stream. Once combined, mix until the batter is uniform. Gently fold in the coconut using a silicone spatula until mixed in. Divide the batter between the prepared pans (approximately 550 grams per pan). Bake until the center springs back when touched, about 35 to 40 minutes. Remove from the oven and allow the cakes to cool in the pans on a cooling rack for 15 minutes. Then use a small offset spatula to gently loosen the edges from the pans. Invert the cakes onto the cooling rack, carefully peel off the parchment, and let them cool completely.

      Prepare the custard filling: In a medium pot, whisk together the coconut milk, cream, sugar, cornstarch, salt, and eggs until fully combined. Cook over medium-low heat, whisking constantly until the mixture thickens, around 2 to 4 minutes. Switching to a silicone spatula can make stirring easier once it starts to thicken. Continue cooking, stirring constantly, until it reaches the first boil (bubbles forming from the center), about 2 to 3 more minutes. Remove from heat, and stir in the butter, vanilla, and coconut until the butter melts and everything is well mixed.

      Transfer the mixture to a medium heat-safe bowl and cover with plastic wrap, pressing it against the surface. Let it cool to room temperature, then refrigerate until fully chilled, at least 2 hours. (To expedite cooling, pour the custard onto a baking sheet and cover with plastic wrap, which increases surface area.)

      Make the frosting: In an electric mixer bowl fitted with the whisk attachment, beat the butter on high speed until white, fluffy, and well-aerated, taking about 7 to 8 minutes. Scrape the bowl, add the vanilla and salt, and beat for an additional minute.

      With the mixer on medium speed, gradually add the sweetened condensed milk in about 4 portions, pouring it in a slow, steady stream, while scraping the bowl occasionally. Continue beating on medium-high speed until the frosting is thick and smooth, taking an additional 1 to 4 minutes. (If the frosting appears broken or grainy, keep mixing and increase the speed to high until it comes together.)

      Transfer one-third of the frosting (approximately ¾ cup or 194 grams) into a pastry bag fitted with a large round tip (about ½ inch/1 cm wide) or cut a ½-inch/1 cm opening from the end.

      Assemble the cake: If necessary, trim the domed tops of the cakes with a serrated knife. Use a small amount of frosting to adhere the first cake layer to a cake board, platter, or stand. Pipe a ring of frosting around the outer edge of the layer. Place about one-third of the custard filling (approximately 1 cup or 300 grams) in the center and spread evenly.

      Add another layer of cake on top and gently press down. Repeat the piping and filling with the next cake layer. Finally, place the last cake layer on top and press down gently. Apply a thin, all-over crumb coat of frosting with a small amount of frosting, then refrigerate the cake for 15 to 20 minutes to set.

      Use the remaining frosting to cover the top and sides of the chilled cake in a thin layer. Pipe a ring of frosting around the outer edge and spoon the remaining custard filling