What can i use to sub buttermilk in baking?

You can substitute buttermilk in baking by mixing one cup of milk (preferably whole or 2%) with one tablespoon of white vinegar or lemon juice. Let it sit for about 5-10 minutes until it thickens slightly, creating a similar acidity and texture. Alternatively, you can use plain yogurt or sour cream thinned with a little water or milk to achieve a similar consistency.