Question: can you substitute fat free evaporated milk for regular evaporated milk?
Answer: In a pinch, most recipes calling for fat-free milk can be adapted to use fat-free evaporated milk—but it's not a 1:1 substitution. Evaporated milk is made when milk is heated and condensed to about half of its original volume. So, to reconstitute it, you'll need to add that lost water back.