Lemon and elderflower drizzle pudding

Name: Lemon and elderflower drizzle pudding
Ingredients: 175g/6oz soft unsalted butter, plus extra for greasing; 50g/1¾oz full-fat Greek yoghurt; 150g/5½oz caster sugar; 100g/3½oz rice flour (or plain flour if you don’t need this to be gluten-free); 75g/2¾oz ground almonds; pinch of fine sea salt; 1½ tsp baking powder (gluten-free if necessary); 3 large free-range eggs, at room temperature; 1 large lemon, zest only; 2 tbsp undiluted elderflower cordial; double cream, to serve; 100ml/3½fl oz undiluted elderflower cordial; 3 tbsp lemon juice