Cheesy Potato Gratin - Serving Dumplings

Ingredients

• 3 pounds starchy potatoes
• 3 ounces sharp cheddar
• 2 ounces grated Parmesan
• 2 tsp fresh thyme leaves
• 1 ¾ cups cream (20% fat)
• ¾ cup whole milk
• 2 tbsp salted butter (melted)
• 1 tbsp olive oil (for greasing)
• 10 fresh sage leaves
• ½ tsp chili flakes (optional)
• 1 tsp salt
• 1 tsp black pepper
• 1 tsp dried onion
• 1 tsp garlic powder
• ½ tsp cayenne pepper (optional)
• ½ tsp smoked paprika