Preheat oven to 350 degrees F (175 degrees C). Grease a mini cupcake mold with butter and coat with sugar.
Mix condensed milk, shredded coconut, eggs, and Parmesan cheese together in a bowl until combined. Pour coconut mixture into prepared cupcake mold, filling each cup to 3/4 full.
Place cupcake mold into a roasting pan about 1 inch larger than the cupcake mold. Pour hot tap water into the roasting pan until it is halfway up the sides of the cupcake mold, about 1 inch.
Bake in the preheated oven until the coconut mixture is golden brown, about 10 minutes.
Cool on a wire rack until the custard can easily be removed from the mold. Place custards into mini paper muffin cup liners.
