Old Fashioned Coconut Cake

Preheat the oven to 350 degrees F (175 degrees C). Grease and flour three 9-inch cake pans. (5 minutes)

Sift together cake flour, baking powder, and salt in a medium bowl. Set aside. (5 minutes)

In a large bowl, cream together the butter and margarine with an electric mixer until light and fluffy. Gradually add the sugar, beating until well combined. (7 minutes)

Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Gradually add the sifted dry ingredients alternately with the coconut milk and vanilla extract, beginning and ending with the dry ingredients. Mix until just combined. Do not overmix. (10 minutes)

Divide the batter evenly among the prepared cake pans. (3 minutes)

Bake for 25-30 minutes, or until a wooden skewer inserted into the center comes out clean. (30 minutes)

Let the cakes cool in the pans for 10 minutes before inverting them onto a wire rack to cool completely. (40 minutes)

While the cakes are cooling, prepare the sour cream soak: In a medium bowl, combine the sour cream, sugar, coconut, and milk. Stir until well combined. (5 minutes)

Once the cakes are completely cooled, place one layer on a serving plate. Use the handle of a wooden spoon to poke holes all over the cake layer. Spread half of the sour cream soak evenly over the cake. Repeat with the second cake layer and the remaining sour cream soak. Top with the final cake layer. (15 minutes)

To make the Swiss meringue buttercream, combine the sugar and egg whites in the heatproof bowl of a stand mixer. Place the bowl over a saucepan of simmering water (double boiler), ensuring the bottom of the bowl doesn't touch the water. Whisk constantly until the sugar is dissolved and the mixture is hot to the touch (about 160°F or 71°C). (8 minutes)

Remove the bowl from the heat and attach it to a stand mixer fitted with the whisk attachment. Beat on medium-high speed until stiff, glossy peaks form and the bowl is cool to the touch. (10 minutes)

Switch to the paddle attachment. Add the vanilla extract and salt. Gradually add the softened butter, one tablespoon at a time, beating well after each addition until fully incorporated. Continue to beat until the buttercream is smooth and creamy. (12 minutes)

Frost the top and sides of the cake with the Swiss meringue buttercream. Sprinkle with the sweetened flaked coconut, if desired. (10 minutes)