Step 1: Preparing the Cake

1. Preheat your oven to 350°F (180°C). While the oven is heating, prepare your pecans by placing them on a baking sheet in a single layer. Bake for 8-10 minutes until golden and fragrant. Be sure not to let the pecans burn, as they can turn bitter. Once done, set them aside to cool.
2. Grease your bundt pan generously with butter and dust it with flour. Make sure to coat every crevice, especially around the center, to ensure the cake doesn’t stick. Alternatively, you can use a pan release spray or homemade “cake goop.”
3. In a medium-sized bowl, whisk together the cake flour, baking powder, and salt. Set this dry mixture aside.
4. In a large mixing bowl, use an electric mixer to whip the egg whites until frothy. Add 1/4 cup of sugar and continue whipping until stiff peaks form. This will help give your cake a light and fluffy texture. Set aside.
5. In another large bowl, beat together the butter and the remaining 1 1/2 cups sugar until light and fluffy. Add the oil and vanilla extract, mixing well. Next, add the egg yolks, one at a time, making sure each yolk is fully incorporated before adding the next.
6. Begin adding the dry flour mixture in thirds, alternating with the buttermilk. Start by sifting in a third of the flour mixture, followed by the buttermilk. Stir until just combined. Repeat with another third of the flour and then the rum, followed by the final third of the flour. Be careful not to overmix, as this can lead to a dense cake.
7. Using a rubber spatula, gently fold the whipped egg whites into the batter until no streaks remain. Be gentle to maintain the airiness created by the egg whites.
8. If you’re using pecans, sprinkle them into the bottom of the prepared bundt pan. Pour the batter over the nuts and smooth it out evenly.

Step 2: Baking the Cake

1. Place the bundt pan in the preheated oven and bake for 60-75 minutes. The cake is done when a toothpick inserted into the center comes out clean, and the edges of the cake start to pull away from the pan.
2. Remove the pan from the oven and set it on a wire rack. Let the cake cool for at least 15 minutes. Once it’s cooled slightly, carefully invert the pan to release the cake. If it sticks, gently tap the sides of the pan to help it loosen.

Step 3: Preparing the Butter Rum Sauce

1. While the cake is cooling, make the butter rum sauce. In a medium saucepan, combine the butter, sugar, and water over low heat. Stir gently until the butter is melted and the sugar has dissolved.
2. Bring the mixture to a boil and let it simmer for 5 minutes while whisking constantly. Then remove the pan from the heat and carefully whisk in the rum. Be cautious, as the mixture may bubble up when the rum is added.
3. Once the sauce is ready, take a toothpick or fork and poke small holes all over the top and sides of the cake. This allows the sauce to soak into the cake and enhances the flavor.

Step 4: Soaking the Cake

1. Pour or brush the butter rum sauce over the cake, doing a little at a time to ensure it soaks in evenly. I usually pour about 1/3 to 1/2 of the sauce at first, then repeat the process until all the sauce is used. The cake should absorb the sauce, resulting in a moist, flavorful cake.

Step 5: Serving the Cake

1. Once the cake has absorbed all the sauce, slice it using a sharp, thin knife. Serve with the remaining sauce on the side, allowing each person to pour extra sauce over their slice if desired. The more sauce you use, the stronger the rum flavor will be.