Pastry:
300g plain flour, plus extra for dusting
50g icing sugar
175g unsalted butter or margarine, chilled and cut into small cubes
1 large egg yolk
A pinch of salt
Finely grated zest of one orange
1-2 tbsp ice cold water
Filling:
225g unsalted butter or margarine at room temperature
225g caster sugar
3 large eggs
50g plain flour
150g ground almonds
½ tsp almond extract, optional
350g rhubarb washed, dried and sliced into 5cm-pieces
2 tbsp caster sugar
Ground almonds and icing sugar for decoration