Preheat the oven to 200'C and place 12 muffin cases in a 12-hole muffin tin.

In a large mixing bowl, cream the butter and sugar together with an electric whisk until pale and fluffy. Add the eggs, yoghurt, milk and vanilla extract and mix again until combined.

Sift in the flour, baking powder, bicarbonate of soda and xantham gum. Fold in using a wooden spoon or spatula until combined. Pour in the raspberries and white chocolate chips and fold in gently until evenly distributed.

Spoon the mixture evenly between the 12 muffin cases, and then place in the oven. Bake for 5 minutes and then turn the temperature down to 180'C. Bake for a further 15-18 minutes and remove from the oven. They should be golden on top and a skewer in the centre should come out clean.

Cool on a cooling rack before eating. Will keep in an airtight container for 2-3 days after baking, but best served slightly warm from the oven.