Layers of creamy potatoes, onions, and Gruyère-cheddar cheese baked to golden perfection for ultimate comfort.
# What You'll Need:
→ 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 - scant 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)
# How to Make It:
01 - Preheat oven to 375°F. Butter an 8-cup ovenproof pie or casserole dish.
02 - Melt butter in large saucepan over medium heat. Add onions and garlic, cooking 6-8 minutes until soft and translucent, without browning. Remove from heat.
03 - In a bowl, whisk together heavy cream, milk, Dijon mustard, nutmeg, salt, and pepper until well combined.
04 - Arrange half the potato slices in prepared dish with slight overlap. Top with half the onion mixture and sprinkle with half the combined Gruyère and cheddar cheeses.
05 - Repeat with remaining potatoes, onion mixture, and cheeses.
06 - Pour cream mixture evenly over layers. Press down gently with spatula to compact layers.
07 - Cover dish with aluminum foil and bake for 40 minutes.
08 - Remove foil and bake additional 20 minutes until top is golden and mixture bubbles at edges.
09 - Let rest 10 minutes before serving. Garnish with chives if desired.