You need:
Liquid measuring cup
1 T lemon juice
scant 1 cup milk

I have never purchased buttermilk from the store… because it only takes five minutes at home, and then there’s no scrambling to find recipes to finish up that last bit of buttermilk you have in the fridge. All it takes is two easy ingredients that you already have on hand.

Add juice to your measuring cup first, then pour milk to top off to 1 cup. Wait five minutes and milk will have curdled and is ready to use. “Recipe” can be halved as needed.