"A lot of cake and cookie recipes call for sour cream which might not be readily available at home. This quick fix tastes exactly like the standard store-bought sour cream and is easy to make."
Combine the milk and vinegar and let stand for 10 minutes. Pour the heavy cream into a jar. Stir in the milk mixture, cover the jar, and let stand at room temperature for 24 hours. Chill before using.
Makes 1 cup
1/4 cup buttermilk can be used instead of milk and vinegar mixture.