Put all the ingredients within easy reach on the kitchen counter.
Place a medium-sized saucepan on the stovetop to make the sauce.
In the saucepan, add the apple cider vinegar.
Add the cayenne pepper to the vinegar and sprinkle in the salt.
Next, add the black pepper to the mixture.
Stir in the tomato paste and ensure it is well-mixed.
Stir the brown sugar into the saucepan until all of the ingredients are mixed.
Pour the mustard into the simmering mixture and thoroughly mix everything with a spatula.
Continue stirring the sauce over medium heat until the desired consistency has been reached. The sauce should thicken and develop a rich texture. Typically, simmering this process for 30 to 35 minutes is required.
The sauce will not stick to the pan and won't burn if it is stirred regularly.
Turn off the heat once the sauce has thickened and cooked for the appropriate amount of time.
Allow the sauce to settle and chill for a while before transferring it to a container for storage.
Your homemade Cattlemen's BBQ Sauce is now ready to use!