This is a lovely, creamy and delicate tart; a drizzle of honey and perhaps a spoonful or so of crème fraîche is all that it needs.
For the pastry
250g/8oz plain flour
175g/6oz cold, unsalted butter, cut into little cubes
1 whole egg
1/2 tsp caster sugar
For the filling
300g/10oz young walnuts, pulsed
5 tbsp double cream
2 medium-sized eggs
A few drops of vanilla extract
30g/1oz unsalted butter, melted
Put the flour, butter and sugar into a food processor and pulse until it is the consistency of wet sand. Add the egg and blend once more; the pastry should gather itself into a ball – you may need to add a tablespoon of cold water if it looks dry. Gather up and wrap in parchment paper and place in the fridge for 30 minutes.
Heat the oven to 180C/350F/Gas4. Roll out the pastry and line a 10in tart tin. Prick with a fork, then cover the base with parchment paper and baking beans and blind-bake for 20 minutes. Remove the beans and paper and return the tart shell to the oven for five minutes to dry out the base. Remove from the oven and allow to cool. Turn up heat to 190C/375F/Gas5.
In a large bowl, combine the ground walnuts, sugar, eggs, cream and vanilla extract. Stir together well to combine and pour in the melted butter. Pour the filling into the cooked tart shell and carefully return to the oven. Bake for 25-30 minutes until the custard is golden-brown and the centre is still slightly wobbly. Remove from the oven and allow to cool a little before serving.