1. Preheat oven to 350 degrees.
2. Peel the bananas, place them in a medium bowl, and mash with a fork.
3. Chop the strawberries, apple, and grapes until minced, and add those to the bowl.
4. Stir in the oil. Add the flour, baking soda, and salt.
5. Put paper or silicone muffin cups in a muffin pan, and pour in the batter, filling each cup about three-quarters full (makes 15 muffins).
6. Bake for about 18 to 20 minutes or until a toothpick inserted comes out clean.
7. Allow muffins to cool on a rack, and enjoy!

Here's the nutritional info for one muffin:

Source: Calorie Count [1]