Place sugar and lemon zest into the TM bowl and mill 10 sec/speed 10.
Add butter and chop 5 sec/speed 7. Add remaining ingredients.
Cook 10 min/80°C/speed 5.
Cook 2 min/90°C/speed 6.
Pour into sterilised jars and seal.This will keep for at least 6 weeks in the fridge. (Never lasts that long in mine, but it may last that long in yours, if you forget you have it in there!)