01 - Preheat oven to 350°F. Grease an 8×8-inch baking dish with butter or cooking spray.
02 - In a large mixing bowl, combine the rolled oats, ground cinnamon, ground nutmeg, baking powder, and salt. Stir until evenly distributed.
03 - Add the finely grated carrots, raisins, and chopped walnuts to the dry mixture. Toss until the add-ins are well coated and evenly dispersed.
04 - In a separate bowl, whisk together the milk, eggs, maple syrup, melted coconut oil, and vanilla extract until smooth and fully incorporated.
05 - Pour the wet mixture into the dry ingredients and stir gently until just combined. Avoid overmixing.
06 - Spread the oatmeal mixture evenly into the prepared baking dish, smoothing the top with a spatula.
07 - Bake for 35 to 40 minutes, or until the center is set and the top is lightly golden. A toothpick inserted in the middle should come out clean.
08 - Allow the baked oatmeal to cool for 10 minutes before slicing into squares. Serve warm on its own or topped with a dollop of yogurt.