Preheat the oven to 350°F. Lightly grease two 9-inch cake pans. Set aside.
In a large bowl, beat cake mix, water, butter, and eggs until combined and smooth (2-3 minutes). Pour into the prepared pans. Bake for 22-24 minutes or until a toothpick inserted in the middle comes out clean.
Let cool in the pan for 15 minutes, then remove from the pan and place cakes on a large serving platter.
Make frosting by beating the butter in a large bowl or the bowl of a stand mixer until light and fluffy.
Add the powdered sugar, milk, vanilla, and salt, and mix to combine. Add milk or powdered sugar as needed to make a smooth frosting. Beat on high for 2 minutes, until light and fluffy.
Frost the cooled cakes. Pat the coconut flakes onto the top and sides of the cake.
Make a snowman face. Add buttons and scarf using candy.