Add all ingredients to a blender or food processor. Make sure the cilantro is loosely packed and not overly compressed, which helps the sauce blend more evenly. If using jalapeño, remove the seeds for a milder flavor or leave some in for added heat.
Blend until smooth and creamy, pausing if necessary to scrape down the sides of the container. This ensures no larger pieces of cilantro or garlic remain and helps achieve a silky, uniform consistency. The mixture should take on a vibrant green color as the cilantro fully incorporates.
Taste the sauce and adjust the seasoning as needed. Add a pinch more salt if the flavors seem muted, or squeeze in a little extra lime juice for added brightness and acidity. Small adjustments can help balance the richness of the mayonnaise and yogurt.
Transfer the finished sauce to a small bowl or airtight container. For the most developed flavor, chill for 15–30 minutes before serving. This brief resting time allows the ingredients to meld, enhancing the garlic and citrus notes without altering the texture.
