Instead, I use vinegar and milk as ingredient substitutions for buttermilk. (kitty photos by Caroline Henri, Dreamstime.com)
Add milk to 1 tablespoon of white distilled vinegar until both ingredients measure 1 cup.
Let stand about 5 minutes. Then measure the amount needed for the recipe.
Try this buttermilk substitution and make my Grandma Heisey's easy, moist Old Fashioned Crumb Cake Recipe. It's a special cake, but you do not need any special ingredients to make it as you probably already have everything on hand. Grandma would make several of these cakes at a time for Grandpa. It was one of his favorites, so his tummy would be happy for weeks!
Grandma Heisey's Old Fashioned Crumb Cake
2-1/2 cups flour
1-1/2 cups brown sugar
1/2 cup butter
1 cup buttermilk
(No buttermilk? Substitute by following the directions above.)
1 teaspoon baking soda
1/4 teaspoon salt
Crumb flour, sugar, salt, and butter. Take out one cup of crumbs for topping. Add the baking soda to the milk and stir. Add to the remaining crumb mixture.
Pour the mixture into a 10-inch pie plate and sprinkle crumbs on top.
Bake about 30 minutes in 350 degrees oven.