Can you substitute evaporated milk for single cream in potato gratin?

Yes. Evaporated milk can be substituted for single cream in potato gratin. Evaporated milk is a good substitute for single cream in potato gratin as it has a similar creamy texture and richness, and will thicken the sauce. However, evaporated milk is sweeter than single cream so you may want to reduce the amount of sugar you add to the recipe to compensate. Additionally, evaporated milk can give the gratin a slightly different flavour, so you may want to experiment with different seasonings to find the right balance for your taste.