- 3 cups all-purpose flour
- 1 tsp salt
- 1 tsp baking powder
- 1/2 tsp baking soda
- 1/2 cup buttermilk
- 1/4 cup dark rum
- 1 Tbsp vanilla
- 1 Tbsp fresh lemon juice
- 1 cup plus 2 Tbsp (2 1/4 sticks) unsalted butter, softened
- 2 cups granulated sugar
- 3 large eggs, plus 1 large yolk
- Rum Syrup
- 2/3 cup granulated sugar
- 1/2 cup dark rum
- 2 Tbsp water
- 4 Tbsp unsalted butter
- 1 1/2 oz. pasteurized egg whites
- 2 cups powdered sugar
- 1/2 tsp vanilla
- 1 tsp coconut extract
- 2 Tbsp unsweetened coconut flakes
Preheat oven to 350° and spray and flour a Bundt pan.
In a bowl, add flour, salt, baking powder, and baking soda and stir to combine.
In another bowl, add buttermilk, rum, vanilla, and lemon juice and stir to combine.
In the bowl of a stand mixer fitted with paddle attachment, add butter and sugar and beat on medium until lighter in color and fluffy. Add eggs and egg yolk, one at a time, and beat until combined.
Add 1/3 dry ingredients and mix on medium-low speed until just incorporated. Add 1/3 wet ingredients and mix on low speed until combined. Repeat with next 1/3 dry ingredients, followed by wet ingredients. Pour into prepared pan and bake until toothpick inserted in center comes out clean, 40-45 minutes. Let cool for 10 minutes, turn out onto rack to cool to room temperature, about 2 hours.
For the syrup, in a saucepan over medium-low heat, add granulated sugar, rum, and water, stir and bring to a boil until sugar dissolves, about 2 minutes. Whisk in butter until smooth. With a bamboo skewer, poke cake all over with fork. Brush cake with syrup and allow to soak for 30 minutes.
In a clean bowl of stand mixer fitted with a paddle attachment, add egg whites, vanilla, and coconut extract and beat until frothy. Add powdered sugar gradually and mix on low speed until sugar is incorporated and mixture is shiny. Turn speed up to high and beat until mixture forms stiff, glossy peaks, 5-7 minutes. Drizzle glaze over cake. Sprinkle with coconut flakes.