Preheat oven to 350 degrees F. Grease and flour 13x9-inch pan.
Prepare cake mix according to package directions. Stir in 1/2 cup pecans. Pour into pan.
Bake at 350 degrees F for 35 to 40 minutes or until toothpick inserted in center comes out clean. Cool completely.
For frosting, combine sugar, evaporated milk, egg yolks and butter in medium saucepan. Cook and stir over medium heat until mixture comes to a boil. Remove from heat. Add coconut, 1 cup pecans and vanilla extract. Stir until thick. Spread on top of cake.