Rhubarb and orange cake - Moje wypieki

Ingredients

• 180 g butter
• 140 g caster sugar
• finely grated zest of 1 orange
• 3 medium eggs
• 150 g plain flour
• 80 g fine semolina
• 1 teaspoon baking powder
• ¼ teaspoon bicarbonate of soda
• 60 ml buttermilk
• 200–250 g rhubarb stalks (unpeeled), cut into 8 cm pieces
• icing sugar, for dusting
• 110 g rhubarb (unpeeled), chopped
• 100 g sugar
• 250 ml orange juice
• 100 ml water