4 tablespoons olive oil, plus more for greasing the pan
1pound sweet potatoes, peeled and cut into 1-inch cubes
Salt and pepper
1 tablespoon chopped garlic
1pound whole wheat farfalle or other cut pasta
1/4cup chopped fresh parsley or chives
2 teaspoons red chile flakes, or to taste
Grated Parmesan cheese for serving
Instructions
Heat the oven to 400°F. Grease a large rimmed baking sheet with a little of the oil. The pan should be large enough to hold all the sweet potato cubes in a single layer without overcrowding; if not, use two pans.
Put the sweet potatoes in the pan, sprinkle generously with salt and pepper, and drizzle with 2 tablespoons of the oil; toss to coat. Roast the sweet potatoes until they brown on the bottom, about 15 minutes; scatter the garlic over the top, stir, and continue roasting until tender, another 15 to 20 minutes.
Meanwhile, bring a large pot of water to a boil and salt it. Cook the pasta until it’s tender but not mushy; start tasting after 5 minutes. When it’s done, drain it, reserving 1 cup of the cooking water. Toss the sweet potatoes with the parsley and red chile flakes, then return the pasta to the pot, add the sweet potatoes, and toss with the remaining oil, adding enough pasta cooking water to coat the noodles. Taste and adjust the seasoning. Serve, passing cheese at the table.