Preheat oven to 325 degrees F. Trim fat from meat. Rub meat with salt and black pepper. In a 6-quart Dutch oven brown roast on all sides in hot oil over medium-high heat. Transfer to a plate.
Add onion, sweet pepper, and garlic to Dutch oven. Cook and stir for 4 to 5 minutes or until onion and garlic are tender and starting to brown. Return roast to Dutch oven. Add broth, pineapple, espresso powder, the 1/4 teaspoon crushed red pepper, and allspice. Bring to boiling.
Bake, covered, for 1 3/4 hours. Add potatoes. Bake, covered, for 45 minutes to 1 hour more or until meat and vegetables are tender.
Transfer meat and vegetables to a platter; cover to keep warm. Bring liquid in Dutch oven to boiling. Reduce heat. Simmer, uncovered, for 10 to 15 minutes or until slightly thickened. Serve sauce with meat and potatoes. If desired, sprinkle with additional crushed red pepper.