Preheat oven to 375°. Lightly oil a 13- by 9-inch baking dish. In a large mixing bowl, toss the squash with 1 tablespoon olive oil, then transfer to a large, rimmed baking sheet and arrange in a single layer.

Roast on the middle rack for 50 to 55 minutes, until the edges are golden brown, and the squash easily mashes with a fork.

Remove from the oven, allow to cool slightly. Transfer squash to a mixing bowl and mash.

(Can be done a day ahead of time and stored in an airtight container in the refrigerator overnight.)

Place cooked pasta in a large mixing bowl.

Then make the béchamel sauce. Melt butter in a large saucepan over medium heat. Add flour gradually, using a whisk to blend it into the butter. Cook until the mixture is a light caramel brown shade, approximately 5 to 7 minutes, being careful not to burn. Slowly add the warmed milk, whisking constantly to keep the mixture from clumping. Cook over medium heat, whisking frequently, until the sauce is the consistency of pancake batter, approximately 10 to 12 minutes.

Remove the sauce from the heat, stir in half the shredded cheese and sprinkle with nutmeg, then season with salt and pepper.

Add the butternut squash and stir to combine evenly throughout the sauce. Mix the butternut-béchamel sauce with the pasta, stirring well to combine, then transfer to the baking dish. Top with remaining cheese, sprinkle with thyme leaves, season with salt and pepper and bake until the cheese is golden brown and the sauce is bubbling, 30 to 35 minutes.

Note: Can be prepared up to the point of topping with added cheese then covered and refrigerated for up to 1 day. Please note that the cooking time may need to be increased as the ingredients will be starting from a colder temperature right out of the refrigerator.

For a slightly creamier finished dish, increase the milk to 5 cups.

Total: $16.71 for 4 to 6 servings; $4.18 per serving for 4; $2.79 per serving for 6.

Farmers' Mac 'n' Cheese Variation with Turnip and Lacinto Kale

Ingredients:

• 1 (1½–pound) Macomber (or Cape) turnip, peeled, trimmed and chopped into ½-inch cubes
• 1 (¾-pound) bunch Lacinato kale, rinsed well, stems trimmed, leaves chopped into 1-inch pieces
• Pinch red pepper flakes

Omit the butternut squash from the master recipe. Toss chopped turnip with 1 tablespoon olive oil, then roast at 375° for 40 to 45 minutes, until lightly browned on the edges and easily pierced with a fork.

Heat 1 tablespoon olive oil in a large sauté pan, then add the kale and sauté until softened, 5 to 7 minutes.

Prepare béchamel sauce (in master recipe) and add the roasted turnip and sautéed kale to the béchamel sauce in place of the butternut squash and nutmeg. Stir to spread turnip and kale evenly throughout the sauce.

Mix the turnip-kale-béchamel sauce with the pasta, stirring well to combine, then transfer to the baking dish. Top with remaining cheese, sprinkle with red pepper flakes, season with salt and pepper, and bake until the cheese is golden brown and the sauce is bubbling, 30 to 35 minutes.