Preheat oven to 350°F. Coat a 12-cup muffin tin with nonstick cooking spray.
Stir together rolled oats, carrots, pecans, raisins, and cinnamon in a large bowl. Whisk together milk, eggs, maple syrup, and vanilla extract in a separate bowl.
Combine oat mixture with milk mixture, and spoon about 1/3 cup batter into each muffin cup, evenly distributing among the cups. Bakeuntil firm, about 30 minutes. Cool 10 minutes. Serve immediately, or wrap cooled carrot cake cups individually, and freeze for up to 1 month. Reheat frozen carrot cake cups in the oven or the microwave.