1In 4- to 5-quart Dutch oven, melt butter over medium heat. Cook onion, celery and garlic in butter 10 minutes, stirring occasionally, until tender. Add broth, sweet potatoes and chopped rosemary. Heat to boiling; reduce heat. Cover; simmer 25 minutes or until potatoes are very tender. Remove from heat; cool 15 minutes.
2Meanwhile, heat 10-inch nonstick skillet over medium-high heat. Add ham; cook until browned and crisp on all sides. Drain on paper towels; cover to keep warm.
3In blender or food processor, place one-third of the potato mixture. Cover; blend on medium speed until smooth. Pour into large bowl. Repeat twice with remaining potato mixture. Return pureed mixture to Dutch oven; stir in peanut butter. Cook over medium-low heat, stirring often, until soup is smooth. Stir in whipping cream, salt and pepper; cook until thoroughly heated. Top individual servings with ham. Garnish with rosemary sprigs.