Preheat oven to 350 degrees F. Lightly spray 2 (8 or 9-inch) round cake pans with butter flavored cooking spray; set aside.
In a large mixing bowl, combine cake mix, mashed sweet potatoes, eggs, coconut extract, evaporated milk, and oil. Use an electric mixer to beat on low speed for 30 seconds. Scrape down sides of bowl and beat for 2 minutes on medium speed.
Divide batter between prepared cake pans. Bake in preheated oven for 45 to 55 minutes or until a toothpick inserted in middle of cakes comes out clean. Let cakes cool in pan for 10 minutes. Invert onto a wire cooling rack to cool completely.
In a medium mixing bowl, combine frosting and rum extract; set aside.
Place 1 of the cooled cake layers on serving plate. Cut a triangle from the bottom corner of a small zip-top bag. Spoon 1/4 cup of frosting into bag and secure top with 1 hand. Use other hand to guide bag and squeeze a thick border of frosting around the edge of the cake layer. Spoon cranberry sauce in the center of frosting border.
Carefully place the other cake layer on top. Frost cake with remaining frosting. Sprinkle with coconut and gently pat to adhere to frosting. Slice and serve.