Chilean Potato Bake with Jack Mackerel, Roasted Leeks and Merkén Oat Crust

Instructions

1. 1

   Preheat the oven to 220°F / 105°C to keep the jack mackerel warm later and to 425°F / 220°C for roasting the leeks; if your oven cannot hold two temperatures at once, roast the leeks first at 425°F / 220°C and then lower the temperature when needed.

2. 2

   Place the potatoes in a pot with cold water and 1 teaspoon of salt. Cook over medium heat for 18 to 20 minutes, until very tender. Drain well.

3. 3

   While the potatoes cook, toss the leeks with 1 tablespoon vegetable oil, a pinch of salt, black pepper, and half of the dried oregano. Spread on a tray and roast at 425°F / 220°C for 15 minutes, stirring halfway through, until tender and lightly browned.

4. 4

   In a large skillet, heat the remaining tablespoon of vegetable oil with 20 g butter. Sauté the onion for 5 minutes. Add the garlic and cook 1 minute more.

5. 5

   Add the jack mackerel pieces to the skillet with the onion and garlic. Season with half of the merkén, the remaining dried oregano, a pinch of salt, and black pepper. Cook for 3 to 4 minutes, just until the fish turns opaque.

6. 6

   Pour the white wine into the skillet and let it reduce for 2 minutes. Fold in the roasted leeks and fresh parsley. Mix gently, adjust the salt, and keep warm in the oven at 220°F / 105°C.

7. 7

   Make the mash: mash the hot potatoes with 20 g butter, milk, cream, salt, and black pepper until rustic but creamy. Stir in 120 g of the grated chanco cheese and mix until melted.

8. 8

   Preheat or adjust the oven to 375°F / 190°C for baking the casserole.

9. 9

   For the crust, combine the rolled oats with the remaining 60 g grated chanco cheese, the remaining 10 g melted butter, and the rest of the merkén until you get a loose, sandy topping.

10. 10

    In a baking dish, spread half of the mashed potatoes. Evenly layer the jack mackerel mixture with onion, garlic, white wine, roasted leeks, and parsley on top.

11. 11

    Cover with the remaining mashed potatoes and finish with the merkén oat crust, spreading it over the entire surface.

12. 12

    Bake the casserole at 375°F / 190°C for 22 to 25 minutes, until bubbling at the edges and golden on top. Let it rest for 8 minutes before serving.