Slow-cooked beef ragu with gnocchi

Preheat the oven to 180°C. In a large saucepan over a medium to low heat, fry the leek in the olive oil and butter for 5 minutes.
Turn up the heat to medium and add the mushroom, sage and garlic. Fry for a further 10 minutes, then add the wine, stirring for 2 minutes, before adding the chicken stock.
Simmer for 10 to 15 minutes, until slightly thicker, before adding the shredded chicken and cream. Add the cornflour, 1 t at a time, to thicken.
Bubble slowly for a further 5 minutes, then season to taste. Spoon onto a large, shallow ovenproof plate.
On a floured surface, roll out the pastry to 3 cm thick. Click here for a perfect shortcrust pastry for this recipe.
Drape over the filling to cover the plate before fitting snugly round the mixture.
Beat the egg yolk, adding a drop of milk to dilute if necessary, then lightly brush the surface with the egg mixture. Bake for 15 to 20 minutes, until golden and crisp.