So many holiday recipes call for evaporated milk, and there's no reason to buy that expensive little can when you learn how to make evaporated milk in just a few minutes! This homemade evaporated milk recipe yields the equivalent of 1, 12 oz. can. If you need evaporated whole milk, add the melted butter. By the way, evaporated milk is simply milk that's had about 60% of it's water content removed, so it's more concentrated, richer and thicker.