Fish Tagine with Tomato and Preserved Lemon — Casablanca Style

Ingredients

• 800 g white-fleshed fish (sea bass or mackerel), skin on, cut into large portions, fully thawed and patted dry if previously frozen
• For the tomato-paprika sauce
• 600 g ripe tomatoes, peeled, seeded, and roughly chopped
• 2 medium onions, finely sliced
• 1 large green pepper (Capsicum annuum), cored, deseeded, cut into strips
• 4 cloves garlic, finely chopped
• 2 tsp sweet paprika
• 1 tsp ground cumin
• 1 pinch ground turmeric (Curcuma longa), small pinch; bridges paprika to preserved lemon without asserting itself
• 60 ml olive oil
• To finish
• 1 preserved lemon, rind only, rinsed, cut into quarters
• 80 g cracked Moroccan olives, rinsed

Method

1. 1
   Warm the olive oil in the base of a tagine or heavy-bottomed braising vessel over a medium flame. Add the onion and pepper strips and cook, stirring occasionally, until the onion is fully softened and beginning to colour at the edges — this slow, patient softening draws out their sweetness, which will anchor the sauce against the sharpness of the preserved lemon later. The onion should be translucent and yielding to the touch, with no raw bite remaining.
2. 2
   Add the garlic, paprika, cumin, and turmeric, then stir to coat the vegetables and cook for one to two minutes — blooming the spices directly in the oil and residual fat of the pan opens their aroma in a way that adding them to the tomatoes later never will. The oil in the pan should take on a deep red-orange hue and smell warm and fragrant, with none of the dusty, raw edge of uncooked spice.
3. 3
   Add the tomatoes, stir to incorporate thoroughly, and raise the heat slightly. Cook uncovered for 25 to 30 minutes, stirring from time to time, until all moisture has evaporated and the sauce is thick, concentrated, and pulls away from the sides of the pan — this is where the dish lives or dies, because a thin or watery sauce at this stage cannot be corrected once the fish is added and will leave the final braise slack and dull. The sauce must coat a spoon firmly, with no pooling water visible.
4. 4
   Lay the fish portions over the reduced sauce in a single layer, then distribute the preserved lemon rind quarters and the cracked olives across the top. Cover the tagine immediately and do not lift the lid during cooking, so the steam that builds inside circulates continuously and cooks the fish evenly and gently without drying the surface. The preserved lemon and olives placed on top, rather than stirred in, allow their salt and brine to fall gradually into the sauce as the steam rises and falls.
5. 5
   Braise over a low flame for 20 minutes, resisting any urge to raise the heat, so the fish eases through to the centre without the outside tightening and turning dry before the middle is done. The fish is ready when the flesh is fully opaque through to the thickest point, flakes under gentle pressure from a spoon, and has taken on the colour of the surrounding sauce — no translucency should remain.
6. 6
   Remove from the heat and rest, still covered, for two to three minutes before serving directly from the tagine — this brief rest allows the sauce, which has been agitated by heat, to settle back around the fish and finish seeping into the flesh. The sauce on the plate should be thick and coating; any visible water separation indicates under-reduction.