01 - Preheat the oven to 350°F. Grease an 8x8-inch baking dish with butter or non-stick cooking spray.
02 - In a large mixing bowl, whisk together the rolled oats, ground cinnamon, ground nutmeg, baking powder, and salt until evenly distributed.
03 - In a separate bowl, whisk together the eggs, milk, maple syrup (or honey), and vanilla extract until smooth and well blended.
04 - Pour the wet mixture into the dry ingredients and stir gently until everything is thoroughly combined and the oats are fully coated.
05 - Fold in the grated carrots, chopped nuts, raisins, and shredded coconut (if using), distributing them evenly throughout the batter.
06 - Pour the mixture into the prepared baking dish, spreading it out into an even, uniform layer.
07 - Bake for 35 to 40 minutes, or until the center is set, the edges are lightly golden, and a toothpick inserted in the middle comes out clean.
08 - Allow the baked oatmeal to cool for 10 minutes before slicing into squares and serving warm.