Name: Potato Leek Gratin
Prep time: 20 min
Cook time: 60 min
Total time: 80 min
Yield: 4
Ingredients: 3 Tbsp unsalted butter; 2 leeks; 1 tsp Diamond Crystal kosher salt; ¼ tsp thyme (fresh or dried); ⅛ tsp freshly ground black pepper; ½ cup heavy (whipping) cream; 1½ lb russet potatoes (3 potatoes); 2 cups Parmigiano-Reggiano or Parmesan cheese (grated); 2 cups Mexican-style shredded cheese; 1 Tbsp panko (Japanese breadcrumbs); 1 green onion/scallion (chopped, to garnish)