Wash the parsley, basil, and chives, then dry them thoroughly. Excess water can make the finished dip thinner than intended. Cut the avocado in half, remove the pit, and scoop the flesh into a food processor or high-powered blender.

Add the Greek yogurt, parsley, basil, chives, lemon juice, olive oil, garlic, salt, and black pepper. Start without adding water. The avocado and yogurt should provide enough moisture for many food processors.

Process for 1–2 minutes, stopping to scrape down the sides as needed. Continue blending until the herbs are finely incorporated and the dip looks creamy and evenly green. If the mixture is too thick for your equipment, add cold water one teaspoon at a time . Avoid adding too much, since the goal is a thick vegetable dip rather than a pourable dressing.

Taste the dip and adjust the lemon juice, salt, or black pepper as needed. Transfer it to a serving bowl. If desired, garnish with finely chopped chives, a few parsley leaves, or a small drizzle of olive oil. Serve immediately with fresh vegetables.