Creamy potatoes layered with Gruyère, cheddar, and caramelized onions, baked until golden and bubbling.
# Needed Ingredients:
→ Vegetables
01 - 2.6 lbs floury potatoes (Maris Piper or Yukon Gold), peeled and thinly sliced
02 - 2 medium onions, thinly sliced
03 - 2 cloves garlic, minced
→ Dairy
04 - 5 oz Gruyère cheese, grated
05 - 5 oz mature cheddar cheese, grated
06 - 1 1/4 cups heavy cream
07 - 3.5 tablespoons unsalted butter
08 - 1/2 cup whole milk
→ Seasonings
09 - 1/2 teaspoon freshly grated nutmeg
10 - 1 teaspoon Dijon mustard
11 - Salt and freshly ground black pepper to taste
→ Topping
12 - 2 tablespoons fresh chives, finely chopped (optional)
# Steps:
01 - Preheat oven to 375°F. Butter an 8-cup ovenproof pie or casserole dish and set aside.
02 - Melt butter in a large saucepan over medium heat. Add onions and garlic, cooking for 6 to 8 minutes until soft and translucent but not browned. Remove from heat.
03 - In a bowl, whisk together heavy cream, milk, Dijon mustard, nutmeg, salt, and black pepper until well combined.
04 - Arrange half of the potato slices in the prepared dish with slight overlap. Top with half of the onion mixture and sprinkle with half of the Gruyère and cheddar cheeses.
05 - Repeat with remaining potatoes, onion mixture, and cheeses.
06 - Pour cream mixture evenly over the layers. Press gently with a spatula to compact the contents.
07 - Cover dish with aluminum foil and bake for 40 minutes.
08 - Remove foil and continue baking for 20 additional minutes until golden and bubbling.
09 - Let rest for 10 minutes before serving. Garnish with fresh chives if desired.