Lightly coat 2 (8-inch) cake pans with cooking spray; set aside. In a large bowl, combine cake mix, butter, buttermilk, egg whites, and extracts. Beat with an electric mixer on low speed for 30 seconds, scraping down sides of the bowl as needed. Beat on medium speed for 2 minutes. Fold in crushed pineapple, coconut, and 1 cup pecans. Divide batter into 2 prepared cake pans. Bake in preheated oven for 31 to 36 minutes or until tester inserted in middle comes out clean. Cool in pans for 10 minutes then turn out on to wire racks to cool completely.
In a small bowl, stir together remaining 1 cup pecans and frosting. With a serrated knife, cut both cakes horizontally to make 4 layers. Frost the top of each layer with 1/2 cup of frosting and stack on top of the next layer. Use remaining frosting to frost the entire outside of cake. Slice and serve.