Need only 1 cup buttermilk for recipe. No need to buy, prepare at home........
1 cup milk (on room temperature)
2 tbsp white vinegar or fresh lemon juice
Place the vinegar in a glass & add enough milk to make 1 cup liquid. Stir to combine and let stand for 10 to 15 minutes, The mixture will begin to curdle.
Use as needed in a recipe, or you can cover and refrigerate until needed.