• Preheat Oven: Preheat your oven to 325°F (165°C). Grease and flour a 12-cup bundt pan thoroughly.

Make the Cake:

• Cream the Butter: In a large mixing bowl, cream the softened butter and granulated sugar until light and fluffy, about 3-4 minutes.
  1 cup unsalted butter, 1 ½ cups granulated sugar
• Add Eggs/Vanilla: Add the eggs, one at a time, mixing well after each addition then add the vanilla.
  4 large eggs, 1 teaspoon vanilla extract
• Combine Dry Ingredients: In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
  2 ½ cups all-purpose flour, 2 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon salt
• Combine Wet/Dry Ingredients: Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk and rum. Begin and end with the dry ingredients. Mix just until combined; do not overmix.
  1 cup buttermilk, ½ cup dark rum
• Transfer to Pan: Pour the batter into the prepared bundt pan and smooth the top.
• Bake: Bake in the preheated oven for 45-55 minutes, or until a toothpick inserted into the center of the cake comes out clean.

Make the Rum Syrup:

• While the cake is baking, melt the butter in a saucepan over medium heat.
  ½ cup unsalted butter
• Add the sugar and water, stirring until the sugar is fully dissolved. Heat at a rapid simmer for 5 minutes, stirring constantly, then remove from heat.
  1 cup granulated sugar, ¼ cup water
• Carefully stir in the rum and vanilla extract (it may bubble up, so stir slowly). Return the pan to the heat for another 1-2 minutes, and continue to stir. Remore from heat and set aside.
  ½ cup dark rum, 1 teaspoon vanilla extract

Soak the Cake:

• Once the cake is out of the oven, let it cool for about 10 minutes in the pan. Then, gently invert it onto a wire rack.
• While the cake is still warm, slowly brush or drizzle the rum syrup over the entire surface, allowing it to soak in. Continue until all the syrup is used.
• Allow the cake to cool completely before serving.