A cake that blends a favorite drink with a rum cake and pound cake. This is dense, but not heavy, and the spicy molasses kick from the dark rum enhances the banana flavor. You may use light or dark brown sugar.
Combine the butter, water, and sugars in a heavy-bottomed saucepan over medium-high heat and bring to a boil. Reduce heat to medium-low and simmer for 5 minutes. Remove from heat and stir in the rum. Set aside and keep warm.
TO MAKE THE CAKE.
Position a rack in the middle of the oven and heat to 350°F Spray a 10-cup tube pan with nonstick cooking spray. Sprinkle the pecans in the bottom of the pan and set aside.
In a large bowl, use an electric mixer to beat together the butter and sugars until light and fluffy.
One by one, beat in the eggs, taking care to mix well between each addition.
Beat in the mashed bananas, vanilla, and rum.
Sift the flour, baking soda, baking powder, and salt over the batter and fold in using a rubber spatula, just until no streaks of flour remain.
Fold in the sour cream.
Spoon the batter into the pan and spread to the pan using the back of a rubber spatula.
Bake about 60-80 minutes, or until a toothpick inserted in the center comes out clean. Transfer to a wire rack and allow to cool for 5 minutes. Use a wooden skewer to poke holes all over the cake and pour 1/4 cup glaze over the cake.
Allow to cool for 5 more minutes. Place a serving platter over the pan and invert to release the cake. Spoon the remaining glaze over the cake, little by little, and let stand until the glaze is completely absorbed by the cake. If the glaze starts to pool at the base of the cake, use a small metal spatual to spread it up and around the sides of the cake. As the glaze cools, it will form a rummy, sugary shell.