The best way to continue King's Gambit Accepted as White after 3 ... Be7 I have some concern when playing King's Gambit as white but it's interesting. After:

[FEN ""]
1.e4 e5
2.f4 exf4
3.Nf3 Be7


What is the best move for white?
The black threat of Bh4+ is not really ones, white should play Bc4 in this position. Releasing the f1 square for the king after the check on h4. After the check white cannot castle anymore but the bishop on h4 is not very happy, black can't play the g8 Knight and need to spend one more tempo on retreating the bishop.

If black don't give the check, white could just occupy the center with the d4 pawn, castle and capture back the f4 pawn with a nice game.