What a lovely find! I've a bit of envy as I haven't seen this in a long time. It appears to by the Witch's Cap Hygrocybe conica or a related Hygrocybe species, a group known as the wax caps. If you see it again, watch for colour changes over time. ... Note that many of the Hygrocybes have been renamed Hygrophorus somewhat recently, I'm not sure if this is one of those. cheers, frog