Turnip, Apple and Cheddar Gratin

• 1 large onion, cut into 1/4 inch slices
• 2 tablespoons olive oil
• 1 12 teaspoons butter
• 1 lb turnip, peeled and cut into 1/8 inch slices,divided
• 12 lb baking potato, peeled and cut into 1/8 inch slices,divided
• 12 lb granny smith apple, peeled and cut into 1/8 inch sliced,divided
• 1 tablespoon chopped fresh rosemary
• 1 tablespoon chopped fresh thyme
• 34 teaspoon fine sea salt
• 34 teaspoon fresh ground black pepper
• 1 14 cups grated extra-sharp cheddar cheese

1. Saute onion in olive oil in a 10 inch cast iron skillet over medium high heat 5 minutes.
2. Cover, reduce heat to medium-low and cook 15 more minutes or until onion is tender, stirring often.
3. Uncover and cook, stirring often, 5 to 10 minutes or until browned.
4. Remove onion from skillet.
5. Add butter to skillet.
6. Layer half each of turnip, potato, and apple slices in skillet, overlapping slices' sprinkle with half each of onion, rosemary, thyme, salt, pepper and cheese.
7. Repeat procedure with remaining ingredients.
8. Bake, uncovered, at 400*F for 40 to 45 minutes, or until tender.
9. Let stand 10 minutes before serving.

onion, olive oil, butter, baking potato, granny smith apple, rosemary, thyme, salt, fresh ground black pepper, cheddar cheese

Taken from www.food.com/recipe/turnip-apple-and-cheddar-gratin-90728 (may not work)