Difficulty: Intermediate
To prepare the potato galette, peel the potatoes and reserve 250 g. Finely grate them using a food processor's fine grid. Drain in a colander for 15 minutes, then squeeze out excess moisture to yield 200 g. Place in a bowl.
Peel and finely chop 100 g sweet onions. In a 24 cm non-stick frying pan, heat half the peanut oil (1/2 tablespoon) and 20 g butter. Add the sugar, salt, pepper, and 2 tablespoons water. Bring to a boil, then add the onions and cook for 5 minutes until caramelized. Stir into the grated potatoes with additional salt, pepper, nutmeg, and thyme flowers. Mix well.
Heat the remaining 20 g butter and oil in the pan. Add the potato-onion mixture and flatten into a pancake using a flexible spatula. Cook for 7 minutes over low heat. Flip and cook for another 7 minutes. Keep warm and cut in half for serving.
For the soles, ask your fishmonger to remove the dark skin, scrape the white skin, and gut them. Rinse and pat dry. Lightly dredge in flour, shaking off excess for a light veil.
Melt 25 g semi-salted butter in a 26 cm non-stick frying pan. Arrange the soles head-to-tail, thick side down. Cook for 10 minutes over low heat until golden, gently basting with butter slivers. Turn with a spatula and cook the second side until golden, basting again. Use a total of 100 g butter, keeping it blond—never browned, a key to authentic flavor.
Arrange the soles on warm plates, spoon over the butter, and serve with the potato galette.
