Grease a baking dish with butter or coconut oil.
In a bowl, combine the cornstarch with the milk and mix well. It will have a glue like consistency.
In a saucepan on medium heat, heat coconut milk, evaporated milk, condensed milk and sugar.
Once the sugar dissolves, add the corn and stir to combine.
Simmer on medium heat for 5 minutes.
Add the cornstarch and cook, stirring constantly until it thickens, about 10 minutes.
Transfer to prepared baking dish. Spread in an even layer.
Chill in the refrigerator for at least 3 hours, but preferably overnight so that it has time to completely set.