In a large bowl, mix flour, baking soda, baking powder and salt. In another bowl, beat together mashed ripe bananas, splenda, egg and butter. Gently mix in blueberries. Stir the banana mixture into the flour mixture just until moistened. Spoon into prepared muffin cups.
3
Bake in preheated oven for 18-20 minutes until a toothpick inserted into center of a muffin comes out clean.