1. Heat oven to 170 degC.
2. Place butter, sugar, ground almonds, eggs, vanilla and flour in a mixing bowl and beat briefly until well combined.
3. Spread this frangipane mixture over your baked pastry base with a spatula.
4. Place the rhubarb on top of the frangipane in lines and sprinkle the extra caster sugar over the top.
5. Bake for 50 to 60 minutes or until golden brown and just set. Remove from oven and allow to cool before removing from baking tin.
6. Serve with vanilla bean icecream or a little whipped cream.

Sweet shortcrust pastry

1. Place butter, sugar, yolks and flour in a mixing bowl and mix together with just enough cold water to bring the pastry together.
2. Knead lightly, roll into a ball, wrap in plastic wrap and refrigerate for 30 minutes or overnight.
3. Preheat oven to 180C. Unwrap pastry, slice thinly and press into a 28cm fluted tart mould with a baking paperlined removable base.
4. Ensure pastry is evenly and thinly spread, about 2mm thick. Remove excess pastry from around edges.
5. Refrigerate pastry base for 10 minutes before lining witha sheet of baking paper.
6. Fill with baking beans and blindbake for 15 to 20 minutes or until golden brown. Allow to cool before removing beans.