Preheat oven to 200°C.
Sift the flour, salt and mixed spice together.
Add the sugar, nuts and carrot and mix through.
Beat the milk, butter, oil, eggs and essence together.
Gradually add to dry ingredients and lightly mix until just moistened.
Do not over mix, batter can still be lumpy.
Spoon into the hollows of a greased muffin pan.
Bake for 20 - 25 minutes or until muffins spring back when lightly pressed with finger.
Allow to cool in pan for 5 minutes before turning out onto a wire rack.
Sprinkle with icing sugar and serve with butter.