Wash lemon hot, dab dry. Grate peel, squeeze juice. Coarsely chop the pistachios, mix with 2-3 tbsp. oil and lemon peel. Season with salt and pepper.
Wash the fish, dab dry and cut into 4 pieces. Sprinkle with lemon juice and season with salt and pepper. Place the fillets on a baking tray covered with baking paper and sprinkle each with 1 teaspoon of oil.
Spread the pistachios on top. Press on a little. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/gas: level 3) for about 20 minutes.
Peel and finely dice the shallot. Mix with vinegar and mustard. Season with salt, pepper and some sugar. Fold in 3 tablespoons of oil.
Wash and halve the tomatoes. Sort salads, wash and shake dry. Mix with tomatoes and marinade. Arrange fish and salad. Baguette tastes good with it.