Preheat oven to 350 degrees. Spray a 9-inch cast iron pan or a 9-inch cake pan with cooking spray.
In a medium bowl, whisk together flour, cinnamon, nutmeg, baking powder, and salt. Set aside.
In a large bowl, whisk together oil, both sugars, eggs, and vanilla extract.
Stir in flour mixture.
Fold in carrots, pineapple, pecans, and coconut.
Pour into prepared pan and bake for 25 minutes.
While the cake is baking, make topping. Stir together all ingredients in a medium bowl.
When coffee cake has baked for 25 minutes, remove it from the oven and sprinkle with topping. Return to oven and bake until a wooden toothpick inserted in center comes out clean, about 10 minutes.
While coffee cake is cooling, make glaze. Use electric mixer to beat cream cheese, milk, vanilla extract and powdered sugar until smooth. Adding powdered sugar gradually will help keep it smooth.