Stir together paprika, chili powder, salt, onion powder, garlic powder, mustard powder, cumin, oregano, Truvia blend and pepper.
Preheat oven to 400°F. Remove neck and giblets from turkey; reserve turkey for roasting pan. Pat turkey dry with paper towel. Rub turkey all over, including under skin and inside cavity, with butter and seasoning mixture.
Place on rack in roasting pan. Add neck, giblets, onion, celery and garlic to pan; roast for 30 minutes. Reduce heat to 350°F; roast for 2.5 hours or until thermometer inserted into thickest part of the breast registers 170°F. If turkey browns too quickly, cover loosely with foil.
Carefully transfer turkey to cutting board and tent loosely with foil. Let stand 30 minutes before carving.
Meanwhile, skim off fat in roasting pan; stir in broth and barbecue sauce. Use your favorite flavored barbecue sauces, such as spicy or sweet.
Cook over medium heat, stirring to scrape up brown bits from bottom of pan; bring to boil. Whisk cornstarch with 2 tablespoons of water; stir into pan. Reduce heat to medium-low; simmer for 6-8 minutes or until thickened and flavorful. Strain and serve with turkey.