Preheat your oven to 325°F (160°C). Grease and flour a bundt pan thoroughly.

In a large mixing bowl, combine the flour, sugar, baking powder, and salt.

Add the softened butter, vegetable oil, and buttermilk to the dry ingredients. Mix with an electric mixer on medium speed for 2 minutes until smooth.

Add the eggs, one at a time, mixing well after each addition.

Stir in the rum and vanilla extract until the batter is well combined.

Pour the batter into the prepared bundt pan, smoothing the top.

Bake in the preheated oven for 50-60 minutes or until a toothpick inserted into the center comes out clean.

Allow the cake to cool in the pan for about 10 minutes before inverting it onto a wire rack to cool completely.

In a medium saucepan, melt the butter over medium heat.

Stir in the sugar and water, bringing the mixture to a boil. Allow it to boil gently, stirring occasionally, until it reaches a thick, syrup-like consistency, about 5-7 minutes.

Carefully stir in the rum, continue to simmer the mixture for an additional 2-3 minutes until it thickens further, resembling a caramel-like texture.

While the cake is still warm, use a skewer to poke small holes all over. Slowly pour half of the butter rum sauce over the cake, letting it soak in.

Once the cake is fully cooled, drizzle the remaining sauce over the top, letting it cascade down the sides.

Allow the sauce to set for a few minutes, slice and serve. Enjoy!