Rhubarb and Custard Tart with Pistachios

Pastry

225g plain flour

pinch of salt

175g soft butter

1 dessertspoon icing sugar

a little beaten egg or egg yolk and water to bind

Filling

600g or a little more rhubarb, cut into small pieces

1-2 tablespoons caster sugar

2 large or 3 small eggs

3 tablespoons caster sugar

1 teaspoon pure vanilla extract

300ml cream

Garnish

45g coarsely chopped pistachio nuts (optional)

To Serve

softly whipped cream

1 x 30.5cm tart tin or 2 x 18cm tart tins