INGREDIENTS
2 1/2 cups
whole milk
1 1/2 lb
Yukon Gold potatoes, peeled and very thinly sliced
2
garlic cloves, smashed
1 tbsp
unsalted butter
1
large leek, trimmed, halved lengthwise, and sliced (about 2 cups)
1 tsp
kosher salt, divided
2 oz
Gruyère cheese, shredded (about 1/2 cup)
1 oz
Parmesan cheese, grated (about 1/4 cup)
1/2 tsp
freshly ground black pepper