How to Make It
Combine garlic, ginger, and, if desired, lemongrass in a mortar and pestle; grind into a paste. Place garlic mixture in bowl of a mini food processor or food chopper. Add soy sauce, lime juice, brown sugar, Sriracha, and egg yolk; pulse until smooth. With processor running, slowly pour oil in a thin stream through food chute, and process until fully blended and creamy. Add cilantro; pulse until blended, about 30 times.