Remove the crust from the bread. Inside the bowl of your food processor, add the bread, horseradish, dill, garlic and Reggiano parmesan. Brush the fish filet with the mustard very lightly. Pat the bread mixture on top of the mustard on each fish filet. In a sautÈ pan, heat 1 tablespoon butter and one tablespoons olive oil. When the butter turn light golden brown, add the fish skin side down and cook for at least 2 to 3 minutes. The skin should be nice and crispy. Do not put to many fish pieces in the same pan. Carefully move to a baking dish always skin side down and bake until tops are golden brown.
In a saucepan, heat the olive oil, when hot adds the onion and cook until translucent. Add the garlic, and when fragrant add the peppers and their juice. Tomatoes, basil and chicken stock and cook for 10 to 15 minutes. In a food processor or using your immersion blender process until very smooth. Strain with a Chinois or fine strainer and adjust seasoning with salt and pepper.