Easy! and by the way Qxa7+ would also result in the checkmate.
this turned up in a game
but erikido point out no pawn grabbing so is was abit of a challenge (to find the other move), just my 2c thought. 
Nice puzzle, but hey pawn grabbing? he has gone of pawn grabbing, maybe just one or two. but look how many pawns you have more him!
Yeah, 1 Qxa7+ is what I thought you were going for.
but, sacrificing the queen for the rook was more aesthetically pleasing
Don't go pawn grabbing.