In medium mixing bowl, combine shredded wheat, flour, soda and salt; set aside.
In large mixing bowl, cream butter and sugars together with an electric mixer. Add eggs, vanilla and bananas; continue mixing until well combined. Slowly add in flour mixture. Add walnuts, if desired.
Divide into a 1 (12 count) greased or paper lined muffin pan. Bake in a preheated 375°F oven 20-25 minutes or until a knife inserted in the center comes out clean.
Remove from pan and place on a cooling rack.