Preheat oven to 425 F. Soak the noodles in warm water.
Meanwhile, using a food processor, finely chop or ground walnuts; core and slice apples; peel and slice the squash.
On a large baking sheet, spread the butternut squash and apple slices. Drizzle with olive oil. Place in the oven and roast for 10 minutes. Set aside.
Reduce oven temperature to 375 degrees.
In a small bowl, combine all the ingredients for the sauce.
Lightly butter a 13x9-inch baking dish. Lay 3 noodles side by side. Drizzle ½ cup of sauce over the noodles. Put ⅓ of squash and ⅓ of apple slices on top. Sprinkle with ground nuts and plenty of parmesan. Repeat layering two more times, finishing with a layer of noodles. Top with brie cheese and drizzle the remaining sauce over the top.
Loosely cover the dish with foil and bake until bubbly, about 30 minutes.
Skip roasting the apples and squash but make sure the slices are really thin.
Substitute brie cheese with mozzarella if you're not a fan, although the flavor will be altered.