Rhubarb & custard sandwich biscuits - Good Food Middle East

Ingredients

• 175g unsalted butter, cubed
• 50g caster sugar
• 50g icing sugar
• ¼ tsp fine sea salt
• 250g plain flour, plus extra for dusting
• 50g custard powder
• 2 egg yolks
• 1 tbsp vanilla bean paste
• 200g rhubarb, trimmed and chopped
• 200g caster sugar
• ¼ lemon, juiced