Sift both flours and the baking powder into a large bowl. Add the white chocolate, bicarbonate of soda, sugar and lemon rind and mix everything together.
Mix together the butter, eggs, cream and vanilla extract in a large jug. Pour the wet ingredients on to the dry ingredients and stir together to combine.
Line a 12-hole muffin tin with paper muffin cases. Spoon the mixture into the cases and bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 25 minutes until risen, firm, pale golden and a cocktail stick comes out clean when it is inserted into the centre of a muffin.
Loosen the muffins with a palette knife and cool on a wire rack. Pierce the muffins several times with a cocktail stick and pour over the sweet wine. Dust with icing sugar to serve.