Merluza en salsa verde is hake in green sauce, but Spanish green sauce is nothing like Italian green sauce. Same words, wildly different concept. Theirs is punchy and zingy and bright, ours is sedate and quiet to the point of dullness. You can add clams and shrimp as much as you like, it´s not an exciting dish.
It´s old fashioned , but the ingredients are too expensive for it to have peasant cachet. We are deep in bourgeois cuisine, and to make things worse, the sauce is thickened by flour. Beyond the pale, really.
Comfort food doesn´t not come more comforting than this, though. White fish, poached in a parsley sauce, over white rice, is perfect for frazzled minds or recovering stomachs. It´s very easy to make, and quick, and so soothing and calming that it might very well put you on the way to recovery so fast that you´ll be wanting that brash Italian salsa verde next.
The classic fish to use is hake, but any white fillet you can find will do, and if it´s more sustainable, so much the better. I have qualms when I buy hake, but here it´s a cheap, unwanted fish, which is weird and I just can´t pass it up.
So anyway: coat the bottom of a skillet with oil, add some chopped garlic and when it dances, chopped parsley. You can add a bit of butter and some shallot and it will be inauthentic but wonderful.
Now a spoonful of flour. Once it dissappears, begin adding stock little by little. It should be fish stock, but vegetable or light chicken or even water is fine. It will thicken, you will stir, add more stock, thicken again, and so on until it will not thicken more, and you will have a thin but recognizably saucy sauce. Now let it cook for a couple of minutes, add your fish, cover and wait until it´s cooked through.
If you have clams then add them with the fish, but remember they hold a lot of liquid so do a thicker sauce.
Serve over rice, plain steamed white rice. Nothing else. An orange afterwards, at most, and maybe some mint tea. This is a quiet, serene meal.