Heat oven to 325°F.

In 4-quart ovenproof Dutch oven, heat oil over medium heat.

Cook onions and bell peppers in oil 10 minutes, stirring occasionally, until tender and beginning to brown.

In medium bowl, mix brown sugar, soup mix, chili sauce, salt and pepper.

Move vegetables to side of Dutch oven.

Place beef, fat side up, in Dutch oven; pour sauce over beef.

Spoon vegetables over beef.

Cover; bake 1 hour 30 minutes.

Uncover; bake 1 hour longer or until beef is tender.

Cover; let stand 10 minutes.

Cut beef across grain into thin slices.

Serve with vegetables and any remaining pan juices.

Garnish with rosemary sprigs.