01Preheat oven to 325°F and grease a 9-inch nonstick cake pan with butter. Heat 1 cup sugar in small saucepan over medium-high heat. Cook by gently swirling the pan, but not stirring, until sugar turns a deep caramel color, about 8 to 9 minutes.
02Pour caramel into prepared cake pan and spread evenly over bottom of pan. Set aside and let cool at room temperature.
03Whisk remaining sugar, condensed milk, evaporated milk, whole milk, eggs and 1/2 cup coconut together in large bowl. Pour into prepared cake pan over cooled caramel.
04Place cake pan inside a large baking pan. Pour hot water inside the baking pan until it reaches halfway up the cake pan.
05Bake until edges are set and flan wobbles just slightly, about 50 minutes to 1 hour.
06Let set at room temperature for 30 minutes. Transfer to refrigerator and chill until cold, about 4 hours. Cut around edge of cake pan. Invert flan onto plate and top with remaining coconut. Slice into wedges and serve.