Plain yogurt and water or milk
When combined with fresh fruit and oats, yogurt makes an excellent, probiotic-rich breakfast or snack. It can, however, be used as the magic, understated ingredient in a wide variety of savory and sweet recipes. Interestingly, plain yogurt works well in place of buttermilk because of its thick texture and tangy, acidic flavor.
If you want to make a recipe that calls for a thin batter, like cake, you can use plain yogurt instead of buttermilk. However, it could work better if you mix the yogurt with water or milk. In order to get a buttermilk-like consistency, whisk a small amount of milk or water into plain, unsweetened yogurt. Depending on the thickness of your yogurt, adjust the proportion, but generally speaking, you'll need around 6 ounces (170 grams) of plain yogurt with 1/4 cup (60 mL) of water or milk to make 1 cup (240 mL) of buttermilk replacement.