Preheat oven to 325°. Line a muffin tin with 12 liners.
Mash bananas in a bowl, set aside.
In a medium bowl, combine flour, baking soda and salt with a wire whisk. Set aside.
In a large bowl cream butter and sugar with an electric mixer. Add egg whites, bananas, apple sauce, vanilla, and 8 tablespoons better'n peanut butter, and beat at medium speed until thick. Scrape down sides of the bowl.
Add flour mixture, then blend at low speed until combined. Do not over mix.
Pour batter into muffin tin halfway, then add 1/2 teaspoon of the remaining better'n peanut butter into each muffin well. Top off each muffin with remaining batter, and bake on the center rack for 25 minutes, or until a toothpick inserted in the center comes out clean.