Cook sweet potato in boiling water to cover 8 minutes or until barely fork tender (not soft); drain well. Spread potato in a single layer in a 13" x 9" pan. Cool; cover and chill at least 8 hours.
Stir together rosemary, salt, and pepper.
Sauté onion in 2 tablespoons hot oil in a large nonstick skillet over medium-high heat until golden. Remove onion to a large bowl.
Increase heat to high. Add 2 more tablespoons oil to skillet, and heat oil until hot. Add half of sweet potato, and sauté 10 minutes or until well browned. Stir in half of rosemary mixture. Add sautéed potato to onion in bowl. Repeat procedure with remaining 2 tablespoons oil, sweet potato, and rosemary mixture; add to potato and onion in bowl, drizzle with honey, and toss gently. Serve immediately.