Butter two 15-inch by 10-inch by 1-inch pans each with 1 tablespoon butter; set aside. Combine cashews and coconut on a 15-inch by 10-inch by 1-inch baking pan. Bake at 350° for 8-10 minutes or until golden brown, stirring occasionally. In a large heavy saucepan, combine the sugar, corn syrup and 1/2 cup water. Cook and stir over medium heat until mixture comes to a boil. Add remaining butter; cook and stir until butter is melted. Continue cooking, without stirring, until a candy thermometer reads 300° (hard-crack stage). Meanwhile, combine the vanilla, baking soda and remaining water. Remove saucepan from the heat; add cashews and coconut. Add baking soda mixture; stir until light and foamy. Quickly pour onto prepared baking sheets. Spread with a buttered metal spatula to 1/4-inch thickness. Cool before breaking into pieces. Store in an airtight container. Yield: about 3 pounds.