Dynamic Trompowsky with homework

This was another dynamic Trompowsky game. When black resigned he was four pawns up. view.chessbase.com/cbreader/2019/1/7/Game262650640.html

​​[Event "Little Big Pawn! vs Chess Canadian - Boa"]
[Site "Chess.com"]
[Date "2018.12.08"]
[Round "?"]
[White "NCM Vas Sladek"]
[Black "Kamal51"]
[Result "1-0"]
[ECO "A45"]
[WhiteElo "2054"]
[BlackElo "1814"]
[Annotator "gaiji"]
[PlyCount "43"]
[EventDate "2018.??.??"]
1. d4 Nf6 2. Bg5 Ne4 3. h4 c5 4. d5 Qb6 5. Nd2 Nxd2 6. Bxd2 Qxb2 7. Nf3 g6 8.
e4 Bg7 9. Rb1 Qxa2 10. Be2 d6 11. h5 f5 12. Bb5+ Kf8 13. Bg5 fxe4 14. Nh4 Bg4
15. f3 exf3 16. O-O Bd4+ 17. Kh1 Qxd5 18. Nxf3 Bxf3 19. Bh6+ Kg8 20. Qxf3 Qxf3
21. Rxf3 $18 Nc6 22. Bc4+ 1-0

 Black to move but it's over because black can't cover two mates, Rf8 # and Bc4 +-. Black resigned after 1. ...Nc6 2. Bc4 +-

---

 Homework

Position after 13. Bg5? 

White had a better move. Can you find it? And the follow up moves?

---

Answer: 13. h6 Bf6 14.e5! dxe5 15. Bc3 threatening to win the Queen with Ra1.