Low-fat Blueberry muffins

Makes 12,

225g self raising flour
1tsp mixed spice
115g caster sugar
3 egg whites
3tbsp butter
150ml low fat or blueberry flavored yogurt
1tsp vanilla essence
115g blueberries

Sift dry ingredients into a bowl with 6 tablespoons of sugar. Whisk egg whites, margarine,vanilla and yogurt in a separate bowl and add the blueberries. fold both mixtures together and separate into 12 paper cases. sprinkle the remaining sugar over the muffin mixture and bake in temperature of 190 C for 25 minutes.