Root Vegetable Gratin

Mushroom Topping

• 2 oz Parmesan cheese, cubed (1 in.)
• 2 oz aged white cheddar cheese, cubed (1 in.)
• ½ oz panko bread crumbs
• ½ oz dried porcini mushrooms
• 1 tsp Italian seasoning

Root Vegetables

• unsalted butter, to grease
• 35 oz water
• 40 oz mixed root vegetables, e.g. sweet potatoes, turnips, yams, purple yams and parsnips peeled, cubed (1 in.)
• ½ tsp salt
• ½ tsp ground black pepper

Sauce

• 4 oz yellow onions, diced (1 in.)
• 2 garlic cloves
• ¼ tsp dried sage
• 1 oz unsalted butter, cubed
• 8 oz heavy whipping cream
• 4 oz vegetable broth
• 2 tsp Dijon mustard
• ½ tsp salt
• ½ tsp ground black pepper
• 1 pinch ground nutmeg