Blend: In a food processor, add ½ cup sour cream, zest of 1 lime, 2 tablespoons fresh cilantro, 1 tablespoon lime juice, 1 teaspoon garlic, and ⅛ teaspoon kosher salt. Blend on high until the consistency is smooth and the cilantro is broken down.
Adjust: Taste and add any lime, cilantro or salt - depending upon your taste.
Cool: If you can, place in the refrigerator for 10-20 minutes before serving and the sauce can thicken back up a bit.