Mackerel, Potatoes & Mustard Sauce

📝 Ingredients

• 8 fresh skin-on mackerel fillets (about 600 g)
• 800 g waxy potatoes
• 1 tbsp olive oil
• 1 unwaxed lemon
• 250 g natural yoghurt
• 2 tbsp wholegrain mustard
• 1 shallot
• 15 g fresh dill
• Salt, black pepper

🍴 Utensils

• Baking tray and baking paper
• Saucepan with steamer basket
• Mixing bowl
• Bowl
• Paring knife
• Wide spatula

📖 Steps

1. Wash the potatoes without peeling them and cut them in half, or into quarters for the bigger ones, into pieces of about 4 cm. Steam them for 20 to 25 min over simmering water, until the tip of a knife slides in without resistance.
2. Meanwhile, make the sauce: peel and very finely chop the shallot. In the small bowl, mix the yoghurt, mustard, shallot, the zest of half the lemon, the chopped dill (keep a little back), salt and pepper. Chill until needed.
3. Preheat the oven to 220 °C. Run your fingers over the flesh of the fillets to find the pin bones and pull them out with tweezers, or cut out a thin V-shaped strip along the line of bones with the knife.
4. Pat the fillets dry with kitchen paper, especially on the skin side: damp skin won't crisp up. Lay them skin-side up on the baking tray lined with baking paper, brush the skin with olive oil and season with salt and pepper.
5. Bake for 8 to 10 min at 220 °C, depending on thickness. The mackerel is cooked when the flesh is opaque and flakes easily with a fork. Don't overdo it: this fish dries out quickly and tastes strong if overcooked.
6. Tip the hot potatoes into the mixing bowl, drizzle with the juice of the zested lemon half, season with salt and pepper and toss gently with 3 tbsp of the sauce: while still hot, they absorb the seasoning much better.
7. Divide the potatoes between the plates and add 2 mackerel fillets per person, golden skin facing up, lifting them with the wide spatula. Spoon over the rest of the sauce, scatter with the reserved dill and serve with the other lemon half cut into wedges.