Citric acid, which naturally occurs in many fruits, particularly those in the citrus family. It´s also known as “sour salt” and gives frostings and fillings a pleasantly tart flavor.

You can find citric acid at times marketed as “sour salt” in the spice aisle at many grocery stores. It is not hard to find.

If my recipe calls for citric acid you can use lemon juice or lemon zest for tartness, But citric acid doesn´t add any liquid to the frostings/ fillings which is perfect if you want a fluffy frosting and it tastes amazing.