Spray muffin pan with cooking spray. Preheat oven to 400°F.
In a large mixing bowl, mix together flour, sugar, baking soda, baking powder, nutmeg, cinnamon, salt, and oats. Set aside.
In a separate bowl, whisk together olive oil, egg, and milk. Mash banana and add to mixture. Grate carrots and stir into wet mixture along with raisins.
Gradually add wet ingredients to dry and mix just until blended. Do not whip.
Pour into prepared muffin tin, and bake for 18-25 minutes. When a toothpick inserted into the center of one muffin comes out clean, they are done.