Zest a lime with a zester until you have 1 teaspoon of zest, then cut the lime in half and squeeze out 1 tablespoon of lime juice, discarding any seeds.
In a medium bowl, combine 8 oz (200 ml/grams) sour cream, 1 clove crushed garlic, the 1 teaspoon lime zest, the 1 tablespoon lime juice, and 1/4 teaspoon salt.
Whisk the mixture until smooth and thoroughly combined.
Taste the crema and adjust the salt, garlic, or lime to your preference.
Notes
You can use¼teaspoon of dried garlic granules instead of fresh garlic.