Combine ketchup, brown sugar, molasses, pineapple juice, water, liquid smoke, ground mustard, paprika, garlic powder, cayenne pepper, salt, and black pepper in a medium pot.

Heat the mixture over medium heat until it boils.

Reduce heat and simmer for 5 minutes, stirring occasionally, until the sugar is dissolved.

In a separate small bowl, whisk together cornstarch and cold water to form a slurry.

Gradually add the cornstarch slurry to the simmering sauce, stirring constantly to prevent lumps.

Simmer for 10-15 minutes, or until the sauce reaches your desired thickness, stirring occasionally.