Sour cream rhubarb squares - Good Food Middle East

Ingredients

• 100g butter, room temperature
• 100g golden caster sugar
• 100g mixed nuts, such as walnuts, brazil nuts, almonds and hazelnuts, roughly chopped (you can buy these as a mixed pack)
• 1 tsp ground cinnamon
• 250g dark muscovado sugar
• 1 large egg
• 225g plain flour
• 1 tsp bicarbonate of soda
• 2 x 142ml cartons soured cream
• 300g rhubarb, cut into 1cm pieces