Italian Doughnuts With Chocolate Sauce

Place potatoes in a saucepan of cold salted water and bring to the boil over a medium heat, then boil gently for 30 minutes or until tender aand then drain.
Push through a potato ricer into a large bowl.
Gently heat milk and butter in a small saucepan over a low heat until butter melts.
Combine flour, 55 grams of the sugar and the yeast in a medium bowl.
While potatoes are still warm, add the flour mixture with the egg and warm milk mixture and using your hand, bring all the ingredients together to form a soft dough.
Divide dough into 4 portions and roll each portion into a 1.5cm thick log and then cut into 10cm lengths and shape each length into a ring to form a doughnut.
Place 3cm apart on a lightly floured tray.
Stand rings, covered with a clean tea towel, in a warm place, for 30 minutes or until they double in size.
Combine cinnamon and remaining sugar in a shallow bowl, then set aside.
To make chocolate sauce, place chocolate in a heatproof bowl.
Heat cream in a small saucepan until hot, then pour over chocolate and stand for 1 minutes, then mix until smooth and then cover with plastic wrap to keep warm.
Half fill a deep frying pan with oil and heat over a high heat, oil is ready when a cube of bread dropped into the oil turns golden in 10 to 15 seconds.
Deep-fry doughnuts in small batches for 1 minute or until lightly golden and then drain on paper towels and then roll in cinnamon sugar.
Serve doughnuts with the chocolate sauce for dipping.