Combine both coconut milks in a small saucepan and simmer over medium heat until the volume is reduced by half, or 14-ounces (the same amount as one can of dairy evaporated milk), about 1 hour.
Recipe by Adventures of a Gluten Free Mom at https://www.adventuresofaglutenfreemom.com/2011/11/how-to-have-the-best-gluten-free-thanksgiving-and-a-recipe-roundup/