Preheat oven to 375 degrees F and spray 8 x 8 baking dish with cooking spray. Set aside.
In a large bowl, add oats, baking powder, cinnamon, nutmeg and salt. Stir. Whisk eggs in a small bowl and add to the bowl along with milk, maple syrup and vanilla extract. Stir well.
Add carrots, raisins and walnuts. Mix to combine, transfer to previously prepared baking dish, level with spatula and bake for 45 minutes or until golden brown on top.
Remove from the oven, let cool for 5 minutes, cut into 6-8 slices and serve warm or cold with a dollop or drizzle (thin out with milk) of yogurt.
Notes
Store: Refrigerate in an airtight container for up to 5 days. Reheat in a microwave.
Freeze: Place in an airtight container for up to 3 months. Thaw on a counter for a few hours.
Quick oats: You can use quick oats but the texture will be softer. I have not tested this recipe with steel cut oats, it might work.