From theory I've encountered on the Catalan, I've understood that when black goes b7-b6 before first playing c7-c6, a good plan for white is to capture on d5. WI've understood that the rational for this might be that after black signaling that they might fianchetto, there's no longer a reason to keep not allow the exchange of the black e pawn, as their light squared bishop is anyway coming out, and that it's better for white that black recaptures with the e pawn than the c pawn (I'm guessing as after black later pushes the c pawn the hanging d- and c pawns might that become weak). However, I find it difficult to then come up with a follow up plan. What more breaks are there for white? Usually, when I still have my c pawn, I go for the e2-e4 break, but that seems less attractive in a case when there's no c pawn and I'd be landed with a isolated d pawn. Thoughts?
[FEN "rnbq1rk1/p1p2ppp/1p2pn2/3p4/2PP4/5NP1/PP1NPPBP/R2QK2R w KQ - 0 8"] 1. Nf3 d5 2. d4 Nf6 3. c4 e6 4. g3 Bb4+ 5. Bd2 Bxd2+ 6. Nbxd2 O-O 7. Bg2 b6 *