Place all ingredients in a medium-large measuring jug.
Using a stick blender, blend until dressing is smooth and cilantro is finely chopped.
Notes
Ingredient notes
Greek yogurt/sour cream: Feel free to use all Greek yogurt or all sour cream in this recipe. I like the combination of the two, but the decision is up to you!
Dairy free: For a dairy free sauce that's still creamy, use 1 avocado in place of the yogurt and sour cream. With the avocado, I recommend using the dressing right away vs storing it for a few days.
Mayonnaise: Technically not necessary, but I like the richness it provides. Feel free to substitute more Greek yogurt or sour cream if you want to skip the mayo.
Lime juice: I highly recommend using freshly squeezed lime juice, it does really elevate the flavor of the dressing.
Garlic powder: I use garlic powder instead of fresh garlic in all of my salad dressings. Fresh garlic, used raw, can be really hard to gauge. It can be very biting and strong, and increase in strength over time if you keep the dressing in the fridge for a few days. Dried garlic powder doesn't do these things, so it provides much more consistent and also tastier results.
Recipe tips
For a thick sauce, reduce the olive oil to 1 tablespoon. We use the regular recipe for tacos, but if you prefer a thicker consistency when used as a sauce, go for the 1 tablespoon of olive oil.
Right after blending, the dressing is runnier vs after it has been refrigerated. If it is too thick for your liking after a couple of days in the fridge, you can stir in an extra tablespoon of either lime juice or olive oil.
I do not recommend making the dressing in a regular-sized food processor, there's just not enough volume. A miniature food processor works much better.
Store the dressing/sauce in a clean bottle or jar, tightly closed, in the refrigerator for up to 5 days.