For the gnocchi, cook the potatoes in salted boiling water for 5-10minutes, or until tender.
Drain and pass through a potato ricer or mash thoroughly.
Mix the potato, egg yolks, flour and cheese together in a bowl until it just forms a soft dough. Season with salt and freshly ground black pepper.
Divide the mixture in half, roll each piece into a 1cm/½in diameter log on a floured surface.
With a sharp knife, cut each log into 2.5cm/1in pieces of gnocchi.
Cook the gnocchi in salted boiling water for 1-2 minutes, or until they float to the surface.
Remove the gnocchi with a slotted spoon and set aside to drain on kitchen paper.
Heat a frying pan until hot, add the oil and the gnocchi and fry for 1-2 minutes, turning frequently, until golden-brown and crisp.
Remove from the pan and set aside to drain on kitchen paper.
For the soup, heat a frying pan until hot, add the oil, onion and squash and fry for 1-2 minutes.
Add the garlic and rosemary and cook for one minute then add the stock and bring to the boil. Simmer for 5-6 minutes, or until the squash is tender.
Blend the soup until smooth, then add the cream and season, to taste, with salt and freshly ground black pepper.
To serve, ladle the soup into soup bowls, pile some gnocchi into the centre of the soup then scatter over the cress and drizzle with pumpkin oil.