Yellow sweet potato gnocchi parmesan

Ingredients:
Japanese yellow sweet potatoes 300 g (10 oz)
Plain (all-purpose) flour 100 g (3½ oz) + extra for dusting
Egg yolk 1
Unsalted butter 2 Tbsp, softened
Rocket (arugula) leaves 100 g (3½ oz), washed and dried
Freshly ground black pepper to taste
Sea salt to taste
Finely shaved Parmesan cheese to taste

Method:
1. Steam potatoes until tender, then peel while still hot. Transfer flesh to a mixing bowl and mash until fine, then let cool until lukewarm.

2. Add flour and egg yolk and mix into a slightly sticky dough.

3. With well floured hands, pinch off pieces of dough the size of small walnuts and roll into balls. Dust them lightly with flour, then press each one onto the back of a fork to mark it with ridges. Gnocchi can be made up to this point and then refrigerated, laid in one layer and covered with cling film (plastic wrap), for 2–3 hours.

4. Just before serving, combine butter, rocket leaves, pepper and salt in a serving bowl and set aside.

5. Bring a large pot of water to the boil over medium-high heat and add gnocchi. When they float and bob about, cook for 30 seconds more, then remove with a slotted spoon and immediately add to the serving bowl. Toss everything together so that butter melts and rocket wilts.

6. Scatter Parmesan shavings on top and serve immediately.