Sweet Potato Cottage Pie

Position a rack in the center of the oven and heat the oven to 425°F. Line a heavy-duty rimmed baking sheet with foil.

Slice the sweet potatoes in half lengthwise and set them cut side down on the baking sheet. Roast until very tender, about 30 minutes

When cool enough to handle, scoop the flesh into a medium mixing bowl. Add the milk, cheese, butter, 1 tsp. salt, and 1/2 tsp. pepper and beat with an electric hand mixer on low speed until smooth and creamy, about 1 minute. Set aside.

Heat the oil in a 12-inch sauté pan over medium-high heat. Add the celery, carrot, onion, and 1 tsp. salt. Reduce the heat to medium and cook, stirring frequently, until the vegetables are soft, fragrant, and starting to turn golden, 10 to 15 minutes. Add the garlic, cumin, oregano, chile powder, and cinnamon and cook for 30 seconds. Add the beef, season with 2 tsp. salt, and cook until no longer pink, about 5 minutes. Tilt the pan and spoon off all but about 1 Tbs. of the fat; return the pan to the heat.

Pour the tomatoes and their juice into a small bowl and crush them with your hands or a fork. Add the tomatoes to the meat and cook, uncovered, until thick, 10 to 12 minutes. Add the olives and raisins and cook for another minute; season to taste with salt.

You can use another size dish for baking the pie, but keep in mind that the thickness of the meat and sweet potato layers will change, which may affect the baking time. Transfer the beef mixture to a 9×9-inch baking dish. Spread the sweet potatoes over the top in an even layer. Bake until bubbling around edges, about 30 minutes. Switch the oven to a high-broil setting and position the rack about 6 inches from the broiler element. Broil the pie until the sweet potatoes are a bit browned, 2 to 4 minutes.

Let cool at least 15 minutes before serving.