Cream of tartar is an important ingredient in many recipes, as it adds flavor, helps stabilize egg whites and prevents sugar crystallization. However, if you’re in a pinch and don’t have any cream of tartar on hand, there are several substitutes that you can use. You can substitute 1 teaspoon of cream of tartar with 1 teaspoon of white vinegar, or 2 teaspoons of lemon juice. Additionally, you can use an equal amount of baking powder as a replacement for cream of tartar. Just be sure to adjust the other ingredients in the recipe accordingly.