if you are out of buttermilk and you need it for a recipe here you go:
You can add 1 tablespoon vinegar or lemon juice to 1 cup milk. Stir and let stand for 5 minutes. Or you can use plain yogurt instead of buttermilk.
I don't always have buttermilk on hand and it's nice if I want to make some biscuits that I can use this to supplement it!