White to move! How should white proceed?
I think 1.Bh4 is the right move here- the key point is that the bishop protects the rook at e1 at a critical point while also being able to block a key check from f2.
1.Bh4 c5 2.Qxb5! Bxe4 3.f3! and white will win the bishop back- from h4, the white bishop has taken over the guard of the rook at e1, and black can't bail out with 3....Qd4+ followed by 4.Bf2 Bc6.
You can compare this line to the more obvious 1.Bd2 where the same line has white blocking the check with the bishop from e3 where it will double attacked only once protected.