Preheat the oven to 350℉ and grease a 10" bundt pan.

In the bowl of a large standing mixer, beat together the butter, flour, superfine sugar, salt, and baking powder. Beat on low for 2 minutes. Then beat in the milk and mix for 30 seconds. With the mixer still on low, add in the eggs, one at a time. Then mix in the molasses, rum, and vanilla extract. Mine for another minute and then fold in the raisins and any extra rum. Blend until the batter is smooth and thick.

Pour the batter in to the bundt pan and bake for 1 hour. Make sure a toothpick inserted into the cake comes out clean.

While the cake is baking, make the syrup. In a small saucepan over medium heat, stir together the butter, sugar, rum, water, and vanilla extract. Bring to a low boil and then remove the pot from the heat and stir until all the sugar is dissolved.

When you remove the cake from the oven, and with the cake still in the mold, use a skewer to poke holes all over the cake and roughly 3/4 of the way deep into the cake.

Spoon the syrup over the cake and let it absorb through the holes. Just keep spooning the syrup over the cake until it is all absorbed. Then let the cake cool completely. Cover it and let it sit at room temperature for at least 2 hours or overnight.

Remove the cake from the pan and serve. This cake will keep in an airtight container, in the refrigerator, for up to 6 days.