Preheat oven to 375°F (190°C).

In a large bowl, combine Splenda, margarine, and egg beaters.

In a separate bowl, whisk together whole wheat flour, salt, and baking powder.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Gently fold in the mashed bananas.

Spoon the batter into a muffin tin that has been sprayed with cooking spray.

Bake for 15-20 minutes, or until a toothpick inserted into the center comes out clean.