puzzle
the puzzle doesnt work and you are wrong it is one move to mate all white has to do is take the back queen and the king will be in check trapped and unable to take the white queen
That pawn can capture White's Queen in that case..
White places his Queen at g7. Black captures the queen with his bishop. White takes the bishop and its checkmate. (or takes White's rook, and the white checkmates at Qxb2)