Preheat the oven to 350º F.
Whisk milk, sour cream and rum then set aside.
In a large bowl whip the butter for 1 minute. Add the sugar and beat for an additional couple of minutes. Mix in the vanilla. Add the eggs and egg yolks, one at a time, mixing just until combined.
Combine the cake flour, baking powder, baking soda, and salt. Add 1/2 of the dry ingredients to the batter at a time, mixing just until combined. Repeat with the milk/sour cream mixture.
Pour into a well prepared bundt pan and bake at 350º F for 50 minutes or until a toothpick comes out clean.
Add ingredients to a saucepan over medium heat. Stir until butter has melted. Bring mixture to a boil, stirring, and boil for 2 minutes.
Poke holes all over the cake and gently pour most of the sauce over the cake, reserving just a little. Let the cake soak up the glaze and then invert onto a platter. Top with remaining glaze and sprinkle a dusting of Florida Crystals® Organic Powdered Raw Cane Sugar.