Today I remembered this position that I saw a few months ago in a tweet by Sergey Karjakin:
[fen "2k5/8/8/BQ6/4K3/8/8/8 w - - 0 1"]
It seemed very easy to me because there are just 4 pieces left but it was much more difficult than I expected. Sergey was asked to solve it in less than five minutes as part of a bet (which he won). White to play and mate in 3. Can you also solve it in less than 5 minutes? :)