1. Bring a saucepan of lightly salted water to a boil over high heat. Add the potatoes, reduce the heat to medium-low, and simmer about 15 minutes, until tender. Drain well. Pass the potatoes through a potato ricer into a bowl. (Alternatively, rub through a sieve.)

2. Add the Parmesan and egg yolk, season generously with salt and pepper, and mix. Divide into 8 equal balls and flatten into little cakes, each 2in (5cm) in diameter. Spread the flour in to a plate, and season with salt and pepper. Coat the potato cakes in the flour and refrigerate until needed.

3. Pour enough oil into a frying pan to come 1/8 in (3mm) up the sides and heat over medium heat. In batches, add the potato cakes and fry for about 2 minutes on each side, or until golden. Transfer to paper towels to drain.

4. Increase the heat to high. Add the capers and fry for about 45 seconds, or until crisp. Drain on paper towels. Place the potato cakes on a platter, sprinkle with the capers, and serve with lemon wedges.