Broiled herring with harissa

Broiled herring:
- 4 whole herring, scaled and gutted
- olive oil
- 1 lemon, thinly sliced
- squeeze of lemon juice
- plain yogurt for serving
- 3 large, fresh, red chili peppers
- 1 roasted red bell pepper in brine, drained
- 2 garlic cloves, roughly chopped
- pinch of saffron strands
- 1 teaspoon ground coriander
- 1 teaspoon ground cumin
- 1 teaspoon tomato paste
- 1 teaspoon red-wine vinegar
- 3 tablespoons olive oil
- pinch of sugar (optional)
Instructions:
Harissa is traditionally made with soaked dried chili peppers, garlic, various ground spices, mint, and olive oil.
- Lightly score the herring on both sides, then season all over with salt and pepper. Oil a baking sheet and arrange the lemon slices on it in one layer. Place the fish on top of the lemon slices. Drizzle a little olive oil and lemon juice over the fish. Sprinkle with a little more seasoning. Refrigerate while you prepare the sauce.
- Split the chili peppers in half lengthwise and scrape off the seeds. Roughly chop the flesh and put it into a small food processor or blender. Core, deseed, and roughly chop the roasted red bell pepper. Add to the chilies. Put the rest of the harissa ingredients, except the sugar, into the food processor with a little seasoning to taste. Blitz until smooth, stopping the machine once or twice to scrape down the sides of the processor bowl. Taste and adjust the seasoning, adding a pinch of sugar as necessary, to balance out the flavor.
- When ready to cook, preheat the broiler. Place the herring under the broiler, 4–5 inches from the heat source, and cook for about 3 minutes on each side. Transfer to warm plates and serve immediately, with the harissa and some plain yogurt on the side.