Add the egg, and when it is well blended beat in the flour and the bananas alternately, adding about one third of each mixture at a time, and continue to beat until the batter is smooth. Gently but thoroughly stir in the chopped nuts and raisins.
Pour batter into a greased loaf pan and arrange the reserved nuts attractively on the top. Bake the bread in the middle of the oven for 50 to 60 minutes, or until a toothpick inserted into the center of the loaf comes out clean. Remove the bread from the oven and let it cool in the pan for 5 minutes, then turn it out on a wire cake rack. Serve the banana bread either warm or cool.