Heat olive oil in large skillet over medium-low heat. Add onions, and stir to coat with olive oil. Cook 15 minutes, or until slightly browned.
While onions are cooking, boil or steam turnips for 20 minutes or until tender. Mash until smooth (like mashed potatoes), and stir in 1/4 tsp rosemary. Keep warm.
Add garlic and the other 1/4 tsp rosemary to onion in skillet. Cook 1-2 minutes, and serve with mashed turnips. Serve.
Yield: 4 servings (serving size: about 1/2 cup)