Preheat oven to 350°. In a large bowl, cream butter and sugar until light and fluffy, 5-7 minutes. Add eggs, 1 at a time, beating well after each addition. Beat in bananas, eggnog and vanilla. In another bowl, whisk flour, baking powder, 1/4 teaspoon nutmeg, salt and baking soda; gradually beat into banana mixture., Transfer to a greased 9x5-in. loaf pan; sprinkle with remaining 1/4 teaspoon nutmeg. Bake 50-60 minutes or until a toothpick inserted in center comes out clean. Cool in pan 10 minutes before removing to a wire rack to cool.