I'd say slowly preparing g4-g5. Of course, avoiding the in-between move Bc5+.

I can't tell, since I'm a patzer player, but the "just developing" moves tend to be... just bad moves. Control of the always-weak b5 square must be granted, and a sensible square for black's lsb is b7 (e4 can't be defended by pawns). True is that moves like a6 or g6 are bad because they allow white to build up his own attack. But this move shoudn't be played without a clear mind on how to manage Nd4...

This Bc8 does normally go to e6 in this variation.

Concerning, but to be taken with a certain grain of salt. The doubled e-pawns, with an isolated enemy e-pawn in front of them would not be a fatal inconvenience, I think. You would also be left with the better of your two bishops, a couple of handy open files, and control of some very interesting central squares. I'd probably play to avoid it too, but I'd also be prepared to accept that position ahead of anything (that I considered) tidier but worse.

Well they have been played successfully in the past. 12....Ng6 gains a tempo by attacking his Bf4 and 12....Bc4 exchanges a bishop.

I probably would've taken the knight off the board here. Something hints at an inaccuracy with Black's move. After the exchange, maybe 14...Nf6 keeps the pawn stationary for the time being.

Black seems here to play "reactively", move by move, instead of showing the reasons behind the moves.

That is true, I did play Nc5 in reaction to his threat to win my d6 pawn.

I was expecting that...

Why I was thinking maybe exchange the lsb for the knight.

All this was a nice calculation for both sides... does this mean that you played Nc5 intentionally, in order to get to save the d6 pawn? Do you see, from here, the "hole" in d5, where BxN is bad for you? I assume you do. But you don't comment it, and this is what I miss. Just my feeling, of course!

Yes, Nc5 was played intentionally to save the d6 pawn.

To make it clear: the problem is that black is not well advided to exchange his last B for the N, nor to have a strong pawn in d5, joinable with c4, and the white diagonal aiming to h7, open. Black has to consider seriously to see what a damage can this N do if left where it is, with Qd7, with a future f5(!?) in mind. Is Qd7 is a bad move?

White still has problems in order to attack on the kingside, but it has a lot of space on the queenside...

It looks very interesting for white to place a R on e1. After it, Wlsb can go to any square covered by the black N in e5. If 19. Re8 was played instead, the idea would be this: 19...(Rc8-random move), 20. Bb4, with Bf5 in mind, and Bf4xN, and Q or Bd3...

Well after f6 I can answer Re1 with a queen move.

He is threatening Bd3 - Qh5...

Yes, but I can simply move my queen to break the pin and then exchange on d3 if needs be. But I move my queen to the wrong square!

Let me guess...

Maybe Rad8?! but like Ion, I can see what comes next...

The problem being that black played f6 in order to be able to recapture without losing the blockade on the d pawn, but in playing this, f6 becomes pinned. In a delicate position like this, and at this rate, this is enough to win...