Gather all the ingredients for your Thai cilantro sauce. In a food processor or high-speed blender, add one cup of fresh cilantro (stems and leaves), two to three green chilies, two peeled garlic cloves, a tablespoon of sugar, two tablespoons of fish sauce, and the juice of one fresh lime. Pour in a few tablespoons of water for blending.

Blend the mixture on high for about 30 seconds to 1 minute, or until you achieve a smooth and vibrant green sauce. You may need to stop and scrape down the sides with a spatula.

Once blended, taste your sauce to check for the perfect balance. Add more sugar for sweetness or lime juice for tang, then blend again briefly to mix any adjustments.

Transfer the sauce to a clean, airtight container. It can be served immediately or stored in the refrigerator for up to one week. Stir well before using if separation occurs.