To my knowledge, there is no vegan buttermilk sold commercially. Luckily though, it is super easy to make your own. Say you need 1 cup “buttermilk”; here’s how you would make it:

Place 1 tablespoon lemon juice, lime juice, apple cider vinegar, or white vinegar in a measuring cup.
Add enough non-dairy milk (of your choosing) until it reaches the 1-cup line; stir with a fork or whisk.
Allow mixture to rest for 5-10 minutes."
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