Commence by combining the granulated sugar, eggs, softened butter, and buttermilk in a spacious mixing bowl. Utilize a mixer to achieve a homogenous mixture.

Sequentially introduce the all-purpose flour, salt, baking powder, and baking soda. Subsequently, incorporate the rum or its alternative (vanilla or rum extract) and continue to mix until well amalgamated.

Ensure the bundt pan or your selected baking vessel is meticulously greased. Transfer the batter into the pan.

Place the pan in an oven preheated to 325°F and bake for a duration of 55 to 60 minutes or until an inserted skewer emerges clean. Once baked, allow the cake to cool in the pan for a minimum of 30 minutes prior to extraction.

In a suitable saucepan, amalgamate the granulated sugar, unsalted butter, water, and rum or its designated substitute.

Place the saucepan over medium heat, stirring occasionally. Ensure the ingredients melt uniformly to form a smooth sauce. It is imperative to avoid reaching a boiling point.

Once the cake has cooled slightly, uniformly drizzle the prepared sauce over it.