Wash the lemons and scrape the zest into a saucepan.
Then squeeze the lemons and add the juice, whole (peeled) garlic cloves, thyme sprigs and chicken stock into the saucepan.
Bring to the boil and leave on high heat – for 5 to 10 minutes. Until the fluid has been reduced by at least half.
Carefully remove the garlic and thyme and let cool for a couple of minutes. Then cut the butter into small squares and add into the fluid.
Pour the fluid into the food blender, and blend until smooth.
Then add the sugar, salt & pepper. Blend for a minute and the lemon thyme sauce is ready for use.