Place garlic, chillies, lime leaves, onion and oil into Thermomix bowl and chop for 4 seconds on speed 6.
Saute for 5 minutes at Varoma temperature on speed 2.
Add remaining ingredinets and cook for 30 minutes at 100°C on speed 3.
Remove lemon grass stalk before pureeing by bringing speed up slowly to speed 9 until well blended. This is quite liquid as opposed to being a paste.
Store in sterilised jars in fridge until use. This should keep up to 6 months without any problem.