1. Heat 1 tablespoon oil in electric cooker using the Sauté function on High heat until simmering.
2. Season beef on all sides with 1-½ teaspoon each salt and pepper.
3. Working in batches and adding additional oil as needed, cook beef 3 minutes, turning until all sides are browned.
4. Transfer meat to clean plate.
5. Add celery, carrots, onions, remaining salt and pepper and sauce to pressure cooker.
6. Nestle beef and any liquids in sauce mixture.
7. Close and lock lid.
8. Cook 45 minutes plus depressurizing. on High pressure.
9. When pressure cooker timer goes off, manually release any remaining pressure.
10. Remove meat from sauce to cutting board and break into large chunks with two forks. Fill bread loaf with beef, sauce mixture, cheese, peppers and basil.
11. Tips to Prepare in the Oven: Preheat oven to 300ºF. Heat oil in large skillet on medium-high heat until shimmering.
12. Season beef on all sides with 1-½ tsp. each salt & pepper.
13. Working in batches, cook beef 3 min. or until all sides are browned.
14. Place onions and sauce in 13x9-inch baking dish; top with beef.
15. Use tongs to coat meat in sauce mixture.
16. Cover tightly with foil. Bake 2-½ to 3 hr. or until meat is fork-tender.
17. Continue as directed.
18. For easy cutting, secure loaf with toothpicks before slicing.
19. Cool leftover beef mixture and store tightly covered in the refrigerator up to 3 days, or freeze for up to 1 month.