Wash the potatoes. Cook in boiling water for about 15 minutes. Quench cold, peel. Peel shallots. Pluck rosemary needles from the stems. Wash lemon and cut into slices.
Place the prepared ingredients on a baking tray greased with olive oil and sprinkled with coarse salt. Season with some chilli. Bake in a preheated oven (electric cooker: 225 ° C/ gas: level 4) for about 10 minutes.
In the meantime, wash the fish and pat dry. Cut garlic crosswise into 1-2 slices. Cut tomatoes into thin strips. Fry garlic and tomatoes in hot fat. Add fish, fry for 3-4 minutes on each side and season with salt.
Everything with salad garnished on a preheated plate.