1. To prepare harissa, place the first 4 ingredients in a spice or coffee grinder; process until finely ground. Heat oil in a small saucepan over medium heat. Add 1 tablespoon garlic and spice mixture; cook 1 minute or until garlic is golden and spices are fragrant, stirring frequently. Add tomatoes, mint, and 1/2 teaspoon salt; reduce heat to low, and simmer 1 hour or until mixture thickens to a paste, stirring occasionally. Remove from heat; chill until ready to use.
2. Preheat oven to 375°.
3. To prepare lamb, combine molasses, ginger, 1 tablespoon garlic, and shallots. Unroll lamb; sprinkle 1 teaspoon salt and black pepper over both sides. Spread half of molasses mixture on top of lamb. Reroll lamb; secure at 1-inch intervals with twine. Place on a broiler pan; rub remaining pomegranate mixture over outside of lamb. Bake at 375° for 50 minutes or until a thermometer registers 125°. Place roast on a platter; let stand 15 minutes. Serve with harissa.