Maria - from Quebradills, Puerto Rico
To make your own buttermilk, add 1-2 teaspoons of lemon juice or apple cider vinegar to each cup of milk. Let sit for a few minutes and stir. The acidity of the juice or vinegar will sour the milk, causing it to curdle slightly. You'll use the same amount of curdled milk in your recipes as you would buttermilk.