Peel and slice the onions. Wash the fish, dab dry and cut into larger pieces. Season with salt and pepper. Heat 1 tablespoon of oil in a large coated pan and briefly sauté the onions in it. Deglaze with lemon juice and 50 ml water. Season with tarragon, salt and pepper.
Add fish and steam for 8-10 minutes. In the meantime, peel garlic and dice finely. Cut the chilli pepper lengthwise, remove the seeds. Wash the pod and cut into fine rings. Heat remaining oil in a pot and fry garlic and chili briefly. Add tomatoes and juice, bring to the boil and let it boil down for about 8 minutes at low heat, stirring occasionally. In the meantime, bake the baguette in a preheated oven (electric cooker: 200 °C/ gas: level 3) for approx. 10 minutes. Remove fish and onions from the pan and drain. If necessary, halve the olives and finally fold them into the tomato sauce together with the fish and onions and heat up again briefly. Wash the tarragon, dab dry and pluck the leaves from the stalks. Chop roughly and sprinkle over the tomato sauce.
Add tomatoes and juice, bring to the boil and let it boil down for about 8 minutes at low heat, stirring occasionally. In the meantime, bake the baguette in a preheated oven (electric cooker: 200 °C/ gas: level 3) for approx. 10 minutes. Remove fish and onions from the pan and drain. If necessary, halve the olives and finally fold them into the tomato sauce together with the fish and onions and heat up again briefly. Wash the tarragon, dab dry and pluck the leaves from the stalks. Chop roughly and sprinkle over the tomato sauce. Arrange on plates and serve garnished as desired with a slice of lemon and chillies. Serve with the baguette