Put all ingredients in a bowl and whisk together until sauce is well blended and smooth. Pour over roast in crock pot or slow. Cook on high for 4 or 5 hours or low for seven to eight hours.
This could also be pulled apart and used in tacos or burritos. Makes good sandwiches, too. You could do this recipe in the oven and cook on 350 degrees for approximately 2 hours until roast is cooked to your satisfaction.