Fill a large pot with salted water and bring to a boil. Add pasta to water and cook for 8 minutes, or until al dente; drain well, and reserve in a large mixing bowl.
Melt 6 tablespoons of butter in a large saucepan over medium heat. Add the garlic, and cook for 1 minute, or until golden. Whisk in flour and cook for 1 additional minute. Whisk in milk, and butternut squash, and bring mixture to a low boil. Reduce heat to low, whisk in Gorgonzola, Brie, fontina, salt, and pepper, until cheese is melted, about 3 to 4 minutes.
Pour cheese sauce over the pasta and stir well to combine. Divide the pasta mixture into buttered individual gratin dishes or a buttered 13 by 9-inch baking dish. Sprinkle pecans and sage over pasta; melt the additional 2 tablespoons butter, and drizzle evenly over the top. Sprinkle Gruyere over the pecans and sage.
Bake for 23 to 25 minutes, or until golden brown and bubbly. Cool 5 minutes before serving.
A viewer or guest of the show, who may not be a professional cook, provided this recipe. It has not been tested for home use.