Combine Ingredients: In a medium-large saucepan, combine all ingredients. Use a whisk to mix thoroughly.
Heat the Mixture: Place the saucepan over medium heat. Stir occasionally until the ingredients are fully combined and just before the mixture starts to boil.
Simmer the Sauce: Reduce the heat to low and simmer uncovered for about 2 hours, stirring every 10–15 minutes to prevent sticking.
Cool and Store: Remove from heat and let the sauce cool for 15 minutes. Use immediately, or store in an airtight container in the refrigerator for up to three weeks.