Method
Add garlic, cilantro and lime juice to a food processor and pulse until finely chopped.
Add the avocados and pulse again, scraping the sides as necessary until smooth.
Add the crema (or sour cream) and spices, then mix until well combined and smooth.
Cool in the refrigerator for about 30 minutes before using.
Notes
I used Greek yogurt once and it dominated the flavor; stick with crema or sour cream for best results.