Place the instant cocoa in a 1-cup heat-proof glass measuring cup. Stir in the 2 tablespoons hot water, mixing well. Stir in enough additional water, milk or coconut milk to make 1/2 cup.
Add a flavored syrup, if you like. Serve over ice cubes or place in blender with ice cubes. Cover and blend until slushy. Serve in a glass or mug topped with whipped topping and drizzled with chocolate syrup, if you like. Makes 1 serving.