Directions

1. Preheat oven to 450 degrees F. Lightly oil a baking sheet or coat with nonstick spray.
2. In a medium bowl, combine Gruyere, white cheddar cheese and Pecorino; set aside.
3. In a small saucepan over medium heat, combine heavy cream, garlic, thyme, Dijon, 1 teaspoon salt and 1/2 teaspoon pepper. Bring to a boil; reduce heat and simmer until flavors have blended, about 2 minutes. Remove from heat.
4. Place half the potato slices in a single layer onto the prepared baking sheet in an overlapping pattern. Sprinkle with half the Gruyere mixture. Top with remaining potato slices and pour the heavy cream mixture evenly over the potatoes.
5. Place into oven, covered, until tender, about 20 minutes. Sprinkle with remaining Gruyere mixture. Place into oven, uncovered, until top becomes golden brown and crusted, an additional 20 to 25 minutes. Let rest 10 minutes before serving.
6. Serve immediately, garnished with chives, if desired.