Coconut Tres Leche Cake is everything you love about a classic tres leche cake, with the added boost of coconut flavor. This semi-homemade recipe starts with boxed cake mix that's drenched in coconut milk and sweetened condensed milk. Then the sweet milk cake is topped with a coconut whipped cream. Baked in a 9 X 13 pan, this easy tres leches cake makes enough to feed a group.