Banana Rum Cake

1 (18.25 ounce) box yellow cake mix
1/8 teaspoon baking soda
2 eggs
1/3 cup finely chopped pecans
2/3 cup light rum
2/3 cup water
1 mashed very ripe banana

Heat oven to 350 degrees F. Grease and flour 2 (9-inch) cake pans.

Combine all ingredients in a large bowl. Blend well. Pour into pans and bake for 25 to 30 minutes.

Frosting:
1/2 cup butter
3 cups confectioners' sugar
2 teaspoons vanilla extract
2 tablespoons rum

Combine butter and confectioners' sugar and blend well. Stir in vanilla extract and rum. Beat well and spread on cake.