Preheat oven to 350°F
Combine flour, baking powder, baking soda, salt, sugar, and melted butter in a large mixing bowl.
In a small mixing bowl combine Bran cereal, bananas, eggs, and vanilla. Allow to sit for at least 5 minutes, or until cereal is soft and mushy.
Spray loaf pan with nonstick cooking spray.
Mix the wet ingredients into the dry ingredients by hand for about two minutes, or until thoroughly blended.
Scrape batter into sprayed loaf pan and place in the preheated oven for 45 minutes. Test the center with a toothpick. It is done when the toothpick comes out clean.
Pull loaf from oven. Butter top of loaf.
Slide butter knife along edge of loaf. Invert on a plate to remove from loaf pan.
