Sour Cream Substitute

For baking -

• 7/8 cup buttermilk or sour milk plus 3 tablespoons butter
• 1 cup yogurt plus 1 teaspoon baking soda
• 3/4 cup sour milk plus 1/3 cup butter
• 3/4 cup buttermilk plus 1/3 cup butter

For cooked sauces -

• 1 cup yogurt plus 1 tablespoon flour plus 2 teaspoons water
• 1 cup evaporated milk plus 1 tablespoon vinegar or lemon juice. Let stand 5 minutes to thicken.

For dips -

• 1 cup yogurt - drain through a cheesecloth-lined sieve for 30 minutes in the refrigerator for a thicker texture.
• 1 cup cottage cheese plus 1/4 cup yogurt or buttermilk, briefly whirled in a blender.
• 6 ounces cream cheese plus 3 tablespoons milk, briefly whirled in a blender

For lower fat -

• 1 cup low-fat cottage cheese plus 1 tablespoon lemon juice plus 2 tablespoons skim milk, whipped until smooth in a blender
• 1 can chilled evaporated milk whipped with 1 teaspoon lemon juice

Found this information at about.com