Step 1: Prepare the Potatoes
1. Preheat Oven: Preheat your oven to 375°F (190°C).
2. Wash and Slice Potatoes: Wash the potatoes thoroughly. Peel if desired, then slice them into thin rounds (about 1/4 inch thick).

Step 2: Mix the Ingredients
1. Combine Soup Mix and Oil: In a large bowl, combine the Lipton onion soup mix with the vegetable oil or melted butter. Mix well.
2. Add Water: Stir in the water until well combined.

Step 3: Assemble the Dish
1. Layer Potatoes: In a greased 9×13-inch baking dish, layer the sliced potatoes evenly.
2. Pour Mixture: Pour the onion soup mixture over the potatoes, ensuring they are evenly coated.

Step 4: Bake
1. Cover and Bake: Cover the baking dish with aluminum foil and bake in the preheated oven for 30 minutes.
2. Uncover and Continue Baking: After 30 minutes, remove the foil and bake for an additional 15-20 minutes, or until the potatoes are tender and golden brown.

Step 5: Serve
1. Garnish: If desired, sprinkle with fresh herbs like parsley or chives before serving.
2. Enjoy: Serve hot as a delicious side dish to your favorite main course.