Mustard BBQ Sauce

1 ounce vegetable oil1 pound chopped onions1 1.2 ounces minced garlic16 ounces white vinegar11 ounces spicy brown mustard2 teaspoons celery seed3 1.2 ounces sugar Salt, as needed Ground black pepper

Heat the oil in a saucepan over medium heat. Add the onions and sauté until translucent, about 4 minutes.

Add the garlic and cook until aromatic, about 1 minute.

Add the remaining ingredients and bring the mixture to a simmer to melt the sugar.

Remove the pan from the heat and allow the flavors to blend, about 30 minutes. Adjust seasoning with salt and pepper.