Preheat oven to 325 F and set rack in the center

grease a 10 inch Bundt pan with butter and dust with flour tapping out excess

sprinkle pecans evenly in the bottom of the pan if using

whisk cake mix and pudding mix then add eggs water oil rum vanilla and salt and beat until smooth and slightly thickened

pour batter into pan and bake until a toothpick comes out clean and the top springs back about 55 to 65 minutes

cool cake in pan on a rack for 10 minutes.

While cake bakes combine butter sugar water and salt in a saucepan over medium heat and bring to a gentle boil

cook stirring until sugar dissolves and syrup thickens slightly about 4 to 6 minutes

remove from heat and stir in rum and vanilla.

Poke the warm cake all over with a skewer while still in the pan

slowly spoon about half the warm syrup over the cake letting it absorb

let rest 10 minutes then invert onto a plate and brush or spoon remaining syrup over the top and sides

cool at least 1 hour before slicing for best texture.