Mix flour, baking powder, baking soda, and cinnamon in a small bowl. Set aside. Mash bananas in a separate bowl. Add in eggs, sugar, brown sugar, & butter. Mix well. Mix dry ingredients into the wet ingredients. Pour batter into lightly greased bread pan. Bake at 350 degrees for 55-60 minutes. Loaf is done when a toothpick inserted in the center comes out clean. Cool in pan for 10 minutes, turn out onto wire rack to cool completely.
This bread can be made into 12 muffins instead of a loaf. Fill cups 3/4 of the way, and decrease baking time to 15-20 minutes. Can add nuts or chocolate chips to the bread, just add after mixing wet and dry ingredients together. Store in air tight bag at room temperature. Keeps for 4-5 days.