Moules-Frites (Belgian Steamed Mussels with Fries)

The mussels need only 3 to 4 minutes in the covered pot, while the potatoes require a lower-temperature first fry and a hotter second fry. Scrub 1000 g mussels under cold running water, remove their beards, discard cracked shells, and leave the rest to drain. Cut 500 g potatoes into thick sticks, soak them in cold water for 10 minutes, and dry every surface thoroughly before they approach the oil. Heat 700 ml neutral oil to 170C and fry the potatoes for 4 to 5 minutes. Take them out while they are tender inside but still pale, then let them rest. Melt 20 g unsalted butter in a pot and cook 60 g chopped shallot with 3 chopped garlic cloves. Add 200 ml dry white wine and let it boil for 1 minute. Tip in the mussels, cover the pot, and steam over high heat for 3 to 4 minutes. Remove the mussels that have opened and discard any that remain closed. Raise the frying oil to 190C and cook the rested potatoes again for 2 to 3 minutes, until their edges are crisp and lightly golden. Season the fries with salt. Finish the mussels and their wine-butter broth with 2 tablespoons chopped parsley and black pepper, then bring both components to the table immediately so the fries do not soften while the shellfish waits.