1 e4 e5 2 Nf3 d6 3 d4 exd4 4 Nxd4 Nf6 5 Nc3 Be7 6 Qf3!? is an interesting idea I stumbled upon recently.

Neither of Bauer's suggestions seem to be comfortable for Black:

A) 6...Nbd7 7 Be2!? (7 Nf5 Ne5 8 Qf4 0-0 =; Borisek-Predojevic, Vidmar mem 2005; 1/2-1/2, 14)  7...Ne5 8 Qg3 0-0 (8...Ng6 9 h4 +/-; Dzhumaev-Habibulla, AsiaCh-T 2008; 1-0, 31) 9 0-0, intending f2-f4, which looks pleasant for White. ...Nbd7-e5 seems premature to me.

B) 6...0-0 7 Nf5 Bxf5  (7...Re8!?) 8 Qxf5 (Of course, this is the point of 6 Qf3)

  B1) 8...Nc6 9 Be3 Ne5 10 Be2 c6 110-0-0! (11 0-0?! b5 12 f4?? falls for a beatiful trick: 12...Nfg4! and the White Queen is stranded. (Dell'Agosti-Schmidt, SUIch-T 2005; 0-1, 45) Otherwise, without f2-f4 it seems hard to make meaningful progress, e.g. 12 a3 a5 13 Rfd1 Qc7 =) 11...b5 12 f4! Nc4 (This time, 12...Nfg4?? fails to 13 Bxg4 g6 14 Qxe5! +-) 13 Bd4 b4 14 Bxc4 bxc3 15 Rhe1! cxb2 16 Bxb2 with a mess that seems to favour White on account of his very active pieces.

   B2) 8...c6! (not mentionned by Bauer) GM Daniel Alsina Leal has recently played this position with the White pieces twice:

       B21) The first time around, he tried 9 Be2 Re8 10 0-0, and didn't get anything following 10...Bf8 11 Re1 Nbd7 12 Be3 b5 = (Alsina Leal-Hoffman , Iberoamerican-ch 2014; 0-1, 64), when all Black did was play all the standard Antoshin moves, and he had no problems.

      B22) The second time, he went for the sharper and more critical 9 Be3 Nbd7 10 0-0-0. His opponent, also a strong GM, played 10...b5 11 f3 Qa5(?!) 12 Kb1 Ne5 13 h4, when White's attack was faster, and he was winning out of the opening. (Alsina Leal-Ibarra Jerez, ESP-ch Rapid 2015; 1-0, 79) Instead, something like 11...a5 might be better, for example, 12 g4 g6 13 Qf4 a4 with unclear play.

This seems like a decent surprise weapon for White, but also not something Black should be afraid of if he knows what he's doing.