01 - Whisk together mayonnaise and sour cream in a medium bowl until completely smooth and no lumps remain.
02 - Add minced jalapeños, jalapeño brine, garlic, cumin, onion powder, salt, and black pepper to the bowl. Mix thoroughly to distribute spices evenly.
03 - Pour in fresh lime juice and chopped cilantro. Stir well to combine all ingredients into a uniform consistency.
04 - Cover the bowl tightly with plastic wrap or lid. Refrigerate for at least 1 hour to allow flavors to develop and meld together.
05 - Remove from refrigerator and give the sauce a final stir. Serve chilled as a dip for tortilla chips, drizzled over tacos, or alongside grilled meats.