01 - Preheat oven to 350°F. Grease an 8x8-inch baking dish with butter or coconut oil.
02 - In a large mixing bowl, combine the rolled oats, ground cinnamon, ground nutmeg, baking powder, and salt. Stir until evenly distributed.
03 - Fold in the finely grated carrots, raisins (or chopped dates), and chopped walnuts, stirring to distribute evenly throughout the oat mixture.
04 - In a separate bowl, whisk together the milk, eggs, maple syrup (or honey), melted coconut oil (or butter), and vanilla extract until smooth and well blended.
05 - Pour the wet mixture into the dry ingredients and stir gently until just combined. Avoid overmixing.
06 - Pour the oatmeal mixture into the prepared baking dish, spreading it into an even layer with a spatula.
07 - Bake for 35 to 40 minutes, or until the center is set and the top is lightly golden brown. A toothpick inserted in the middle should come out clean.
08 - Remove from the oven and allow to cool for 10 minutes before slicing into portions. Serve warm as is, or topped with a dollop of yogurt.