Filling: Cut butternut squash in half and sprinkle with salt. Bake in the oven with olive oil until tender, approximately 45 minutes. Puree squash and mix with grated parmesan cheese, nutmeg and chopped walnuts. Set aside.
Dough: Mix flour and eggs with one ounce of butternut puree. Roll dough out paper thin and cut into 3" x 3" squares. Brush paste squares with egg wash. Put a portion of the filling into the middle of the pasta squares and fold it like a triangle. Then wrap the two edges on top of each other, creating a hat-shaped ravioli. Boil in hot water and salt until they float, approximately 3 minutes.
In a sauté pan put butter and sage leaves and cook them until crisp. Place 4 ravioli on a plate over marinara sauce. Sprinkle with parmesan cheese and finish by pouring brown butter and sage on top of the ravioli. Bon Appetito!