Preheat oven to 325°F and coat loaf pan with cooking spray.

In a small bowl, cream butter and Splenda.

Beat in eggs and vanilla.

In a separate bowl, combine flour, baking soda and salt.

Add flour mixture to creamed mixture, alternating with mashed banana.

Fold in walnuts.

Transfer to loaf pan and bake for 50-55 minutes or until a toothpick inserted in the center comes out clean.

Cool for 10 minutes before removing from pan to a wire cooling rack.