1 medium onion
2/3 cup ketchup
2 tablespoon tomato paste
2 tablespoon butter
2 tablespoon soy sauce
2 tablespoon vinegar
1 tablespoon worcestershire sauce
3 tablespoon brown sugar
2 teaspoon dry mustard
1 boneless turkey breast half (about 3 1/2 lbs.)
1. Preheat the oven to 425-degrees. Line a roasting pan with foil.
2. Make the barbecue sauce: Coarsely chop the onion. In a small saucepan, combine the onion, ketchup, tomato paste, butter, soy sauce, vinegar, Worcestershire sauce, sugar and mustard. Bring to a boil over medium-high heat, stirring until well blended. Remove pan from the heat and set aside.
3. Place the turkey breast on the prepared roasting pan and brush the turkey with one-fourth of the barbecue sauce. Roast the turkey for 15 minutes.
4. Remove the turkey from the oven and reduce the oven temperature to 325-degrees. Brush the turkey with most of the remaining sauce and roast it, basting it periodically with the remaining sauce, until the turkey registers 170-degrees on a meat thermometer, about 1 hour and 45 minutes longer.
5. Let the turkey stand for 5 to 10 minutes before slicing and serving. Bring any leftover basting sauce to a boil and serve it on the side.