Add the ingredients to a food processor bowl. Process until smooth, about 30 seconds, scraping down the sides of the bowl as needed.: As you pulse, notice the fresh scent of chopped herbs and the creamy tang coming together, a green steam of aroma rising as the blades work. This is the moment when separate flavors start to meld into a unified profile, so use a bowl size that gives the herbs room to move for even blending. A common mistake is overcrowding the bowl which can leave larger herb bits, so pulse in short bursts and scrape the sides often to ensure an even puree.
The dressing is best chilled in the freezer for 30 minutes or for at least 2 hours in the refrigerator. (It will thicken up a bit after being chilled.): The sound of the processor changes as the texture transforms from coarse to velvety, shifting from a louder chop to a steady hum. You should see a uniform pale green mixture with tiny flecks of herb, and it should feel silky on the spoon. If it seems too thick, drizzle a little olive oil to help it emulsify. Avoid overprocessing which can heat the herbs and make the dressing darker and slightly bitter.
After chilling, adjust the consistency by adding additional yogurt for thicker or olive oil for thinner. Season with freshly cracked salt, pepper, and lemon juice if desired.: Chilling deepens the flavors and lets the acids and dairy knit together, resulting in a rounder taste. When you chill it briefly in the freezer you speed up that process, but in the refrigerator the flavors develop more gently. A mistake is serving immediately, which may taste grassy and less integrated, so be patient and let the flavors harmonize.
It will thicken up a bit after being chilled: Expect a firmer texture after cooling, with the aroma mellowing and the tang becoming subtler. The change in mouthfeel helps the dressing cling to salads, so if you planned to drizzle it, be ready to thin it slightly. Overthinning with too much liquid will dilute flavor, so add thinning agents sparingly.
After chilling, adjust the consistency by adding additional yogurt for thicker or olive oil for thinner: When you taste after chilling, focus on texture first, then balance. Adding small amounts, a teaspoon at a time, helps you reach the ideal viscosity. If you add too much Greek yogurt you can make it overly tangy and dense, while too much olive oil can make it feel greasy, so proceed carefully and taste between additions.
Season with freshly cracked salt, pepper, and lemon juice if desired: Final seasoning is where the dressing comes alive, so taste and adjust. Freshly cracked salt brightens the whole mixture, black pepper adds warmth, and a squeeze more lemon can bring back zip if chilling dulled the acidity. A common misstep is over-salting early, since flavors concentrate after chilling, so season lightly and revisit after the rest period.