1. Place the BBQ sauce in a saucepan and turn heat to low.
2. Then whisk the flour or cornstarch with cold water in a small bowl.
3. Add the mixture to the sauce and turn the heat to medium.
4. Let the sauce come just barely to a boil and then reduce the heat to low.
5. Allow the sauce to simmer for about 5 minutes.
6. Use a wooden spoon to check for desired consistency—you want it to stick to the spoon.
7. Remove the saucepan from the stove and let your sauce cool.