Mix one tablespoon of lemon juice or vinegar with one scant cup of milk and let stand at room temperature for 5-10 minutes. The mixture will thicken into small curdled bits which you can use as buttermilk in your recipe.
Technically, yes; however, sweet and sour sauce is a specific type of sauce, just like soy sauce or BBQ sauce. It is named so because it tastes both sweet and...