Gratin Kentang Salmon

Bahan-bahan (6 porsi)

• ½ cup whole milk
• 1½ cups heavy (whipping) cream
• 3 russet potatoes ((830 g, 1.8 lbs))
• 1 cup Parmigiano-Reggiano or Parmesan cheese ((3.4 oz))
• 1⅓ cups Homemade Salmon Flakes
• 2 Tbsp panko (Japanese breadcrumbs) ((skip for gluten-free))
• 1 tsp Diamond Crystal kosher salt
• ¼ tsp freshly ground black pepper
• ¼ tsp dried thyme ((or double the amount if you use fresh thyme; more for serving; optional))