Instructions

1. The base of this Caramel Frosting is a homemade caramel sauce.  In a heavy saucepan, combine the brown sugar, butter, and milk. 
2. Cook and stir over low heat. This is an important part of the process. If you rush through this step, your caramel sauce might turn out grainy, which means your frosting will be grainy. You don't need to stir constantly, but you do need to stir often. Once all the butter is completely melted, set a timer and stir continuously for at least 1 minute.
3. Increase the heat to medium.  Do not stir. 
4. Cook for 3-6 minutes. If you have a candy thermometer, cook the sauce until it reaches 230 degrees.  If not, cook until bubbles form across the entire surface of the sauce and the mixture turns the color of amber. For us, that is usually around 3 minutes. The length of cooking time depends on how big or small your pan is. If you are using a small pan, the mixture might take up to 6 minutes to reach this state.  In a bigger pan, it might only be around 3 - 3 1/2 minutes.
5. Remove the caramel mixture from the heat and transfer it to a bowl or a glass measuring cup.  It will be very hot so you want to make sure the container is heat-resistant. Cool to sauce room temperature.  The Caramel Sauce will thicken as it cools and it might be a little grainy. This is fine.
6. Once the caramel mixture has cooled, add it to a mixing bowl with the powdered sugar.
7. Gradually mix the caramel sauce with the powdered sugar until the frosting is combined and is the desired consistency.
8. Add milk, a teaspoon at a time, if the frosting is too thick.