To make the cake: Preheat oven to 325°F. Spread chopped nuts in the bottom of greased and floured bundt pan. Mix rest of ingredients together. Pour batter over nuts and bake for about 1 hour, or until an toothpick inserted into cake comes out clean. Cool, then invert on serving plate. Prick top with fork.
To make glaze: Melt butter in saucepan. Stir in water and sugar. Boil 5 minutes, stirring constantly. Remove from heat. Stir in rum. Spoon and brush onto rum cake.