In a small saucepan combine the cranberries water and sugar and bring to a boil. Simmer over medium heat until the cranberries burst, about 4 minutes.
Preheat oven to 350°F. Lightly spray a loaf pan with baking spray.
In a medium bowl, combine flour, baking soda and salt with a wire whisk. Set aside.
In a large bowl cream butter and brown sugar with an electric mixer. Add egg whites, bananas, and vanilla, and beat at medium speed until thick. Scrape down sides of the bowl.
Add flour mixture and blend at low speed until combined, do not over mix.
Fold in cranberries and pour batter into the prepared loaf pan; sprinkle with turbinado sugar on top and bake in the center rack for about 60 minutes, or until a toothpick inserted in the center comes out clean.
Transfer the pan to a wire rack and let the pan cool at least 25 minutes, bread should be room temperature before slicing.