Sprinkle the hake with salt and black pepper. Pour the wine over them and let stand for 30 minutes. Grease a tray and at the bottom, distribute onion rings, tomatoes, arrange the fish fillets on top and above them - add a few slices of lemon.
Pour in the white wine you used to marinate, the juice of the second lemon and trickle the olive oil in. Put it to bake in a moderately heated oven.