Preheat oven to 350 degrees. Grease a 9x13 baking dish with nonstick spray. Set aside. Set a large skillet over medium heat. Add oats and pecans. Toast them for about 5 minutes, or until you see them start to brown. Stir occasionally. Remove from heat.
In a large bowl, whisk toasted oats and pecans, shredded carrots, raisins, baking powder, spices, salt, and 1/2 cup of brown sugar until evenly combined. Whisk in melted butter until combined.
In a separate medium bowl, whisk eggs, milk, and vanilla together until combined. Pour into dry ingredients and fold together just until combined. Do not overmix!
Pour oatmeal into prepared baking dish. Sprinkle remaining 2 tablespoons of brown sugar over the top. Prepare cream cheese icing by whisking together softened cream cheese, sugar, and vanilla together. Scoop into a plastic storage bag. Cut off a corner of the bag and squeeze out the icing through that hole into diagonal stripes on the oatmeal in the baking pan.
Bake oatmeal until set and no liquid remains, about 35 minutes. Remove from oven and let cool for 10 minutes before scooping into servings.