Potato-Horseradish Gratin with Caramelized Onions

Ingredients

• 2.5 pounds baking potatoes 
• 1 tablespoon balsamic vinegar 
• 0.3 cup butter 
• 0.3 cup parsley fresh divided chopped
• 2 cups half-and-half 
• 0.5 cup horseradish cream-style
• 2 large onions thinly sliced
• 1 teaspoon pepper divided
• 1 teaspoon salt divided
• 1 teaspoon sugar 
• 4 ounces swiss cheese shredded

Equipment

• frying pan
• oven
• baking pan

Directions

1. Cook potatoes in boiling water to cover 20 minutes or until almost tender.
2. Drain and cool slightly. Peel potatoes, and cut into 1/4-inch-thick slices. Arrange potato slices in a lightly greased 13- x 9-inch baking dish.
3. Sprinkle with 1/2 teaspoon salt and 1/2 teaspoon pepper.
4. Stir together half-and-half and horseradish, and pour over potato.
5. Bake, covered, at 400 for 40 minutes.
6. Melt butter in a large skillet over medium heat.
7. Add onion, remaining1/2 teaspoon salt, and remaining 1/2 teaspoon pepper; cook, stirring occasionally, 20 minutes; add sugar, and cook, stirring occasionally, 5 to 8 minutes or until onion is caramel colored.
8. Stir in vinegar, and cook 2 minutes or until liquid evaporates.
9. Remove from heat, and cool 5 minutes. Fold in cheese and 2 tablespoons parsley.
10. Uncover potato; top with onion mixture. Reduce temperature to 35
11. Bake at 350 for 30 minutes.
12. Let stand 5 minutes; sprinkle with remaining 2 tablespoons parsley.