Place all of the ingredients in a blender or food processor and blend until smooth. Season with salt, to taste.
Transfer to a jar or squeeze bottle and serve immediately, or refrigerate until ready to serve.
Notes
This sauce for fish tacos stays fresh in the fridge for about 5 days. Just keep it in a sealed jar or squeeze bottle.
The consistency of the sauce will naturally thicken as it chills in the fridge. To thin it out, stir in a little lime juice or a small splash of water until it thins out.
I don’t recommend freezing the sauce. After thawing, the dairy tends to become gritty and the consistency isn’t as creamy and smooth.