Heat the olive oil in a frying pan over a medium heat. Add the beef strips and fry until browned.

Add the onion and garlic and fry for 2-3 minutes, until softened.

Add the hot chicken stock, bring to the boil and deglaze the pan by stirring and scraping the bottom of the pan with a wooden spoon.

Add the white wine vinegar, cream and blue cheese. Boil to reduce the liquid volume by half, then season, to taste, with salt and freshly ground black pepper.

To serve, pour into a warm dish and garnish with the mint sprig.