Sweet Potato Cottage Pie
Sweet potato cottage pie is essentially ground beef simmered in red wine sauce and smothered with mashed sweet potatoes. Comfort food that's stealthy healthy. Doesn't get any better than that.
For the mashed sweet potato topping
Make the beef ragout
Preheat the oven to 350°F (175°C).
Heat the olive oil in a large heavy saucepan over medium heat. Add the onion and cook, stirring occasionally, until soft and translucent, 4 to 5 minutes. Add the garlic and sauté for 1 more minute. Add the ground beef and cook, stirring and crumbling it with a spoon, until well browned, about 5 minutes. Spoon off and discard any fat and season the beef with salt and pepper to taste.
Add the tomato purée paste, cinnamon, nutmeg, bay leaves, and wine to the pan and simmer over low heat for 10 to 15 minutes. Remove from the heat and discard the bay leaves.
Make the mashed sweet potato topping
Meanwhile, bring a pot of salted water to a boil. Peel the potatoes and sweet potatoes, cutting them into 1 1/2-inch (4-cm) chunks. Toss them in the boiling water and cook until tender, 8 to 12 minutes. Drain the potatoes and return them to the pot. Add the butter and begin to mash with a handheld potato masher or the back of a sturdy spoon. Gradually add the warm milk, the nutmeg (if using), and the Parmesan cheese. Mash until smooth. Season with salt and pepper to taste.
Assemble the sweet potato cottage pie
Scrape the ground beef mixture into a 2-quart (1.9-liter) casserole or other ovenproof dish, such as an 8 1/2-by-11-inch baking dish and smother it with the mashed potatoes. Slide the dish in the oven and bake until golden brown and bubbling, 30 to 40 minutes. Let stand for at least 5 minutes before scooping and serving straight from the dish.