Preheat the oven to 350 degrees F. Grease an 8×8-inch baking pan with nonstick cooking spray and set aside.
In a large bowl, mix together the oats, grated carrots, coconut, brown sugar, cinnamon, baking powder, ginger, salt, and nutmeg. Stir in the raisins, if using.
In a medium bowl, whisk together the milk, melted butter, egg, and vanilla. Pour the wet ingredients over the oat mixture and stir until combined. Fold in the raisins and nuts, if using.
Pour the mixture into the prepared pan. Bake for 40 minutes, until the top is golden and oatmeal is set.
Meanwhile, make the cream cheese maple glaze. In a small bowl, use a spatula to combine the cream cheese, maple syrup, and vanilla. Once combined, switch to a whisk and whisk until smooth.
Let the oatmeal cool for 5 minutes. Cut the baked oatmeal into squares and serve with a drizzle of maple cream cheese glaze.