Preheat oven to 350. In a large bowl, mash the bananas, sugar, oil, eggs and vanilla with a potato masher Ė donít worry about getting all the lumps out. It will look sort of cottage-cheesy.
Add the flour, cinnamon, baking soda and salt and stir until almost combined; add raisins or berries and stir just until blended. Divide among muffin tins that have been lined with paper liners, filling them almost full, and bake for 20-25 minutes until golden and springy to the touch.