In a small bowl, mix the American chili powder, black pepper, and salt. In a large bowl, mix the ketchup, mustard, vinegar, Worcestershire, lemon juice, steak sauce, molasses, honey, hot sauce, and brown sugar. Mix them, but you don't have to mix thoroughly.
Over medium heat, warm the oil in a large saucepan. Add the onions and saute until limp and translucent, about 5 minutes. Crush the garlic, add it, and cook for another minute. Add the dry spices and stir for about 2 minutes to extract their oil-soluble flavors. Add the wet ingredients. Simmer over medium heat for 15 minutes with the lid off to thicken it a bit.
Taste and adjust. Add more of anything that you want a little bit at a time. It may taste a bit vinegary at first, but that will be less obvious when you use it. Remember, it is going on meat and will be cooked once again. Strain it if you don't want the chunks of onion and garlic. I prefer leaving them in. They give the sauce a home-made texture. You can use it immediately, but I think it's better when aged overnight. You can store it into clean bottles in the refrigerator for a month or two.
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