Melt the butter in a large skillet over medium heat and add the butternut squash. Cook until the squash is just starting to caramelize and is golden brown, about 10 minutes. Add the water to cover and cook until the squash is tender, about 20 minutes. Drain. Transfer the squash to a food processor fitted with a metal blade. Add the amaretti, bread crumbs, Parmesan cheese, nutmeg, salt and pepper and blend until smooth. Flour a large cutting board or work surface. Place 2 cups of the flour and the salt on the board and make a wide well in it. Place the eggs and egg yolks in the well. With a fork, follow the perimeter of the well, bringing in small amounts of flour and continuing all the way around, until gradually most of the four is absorbed. If necessary, add up to 1/2 cup of the remaining flour. Divide the dough into 2 pieces. Put the dough through a pasta machine, folding into halves each time and reinserting 15 to 20 times, to knead it. Continue until the pasta is paper-thin. Lay out the sheets of dough and cut them into 4-inch squares; you should have about 40 to 42 squares. Place 1 heaping tablespoon of the filling on one corner of each square. Fold over the filled portion, press down around the filling, and place on a baking sheet lined with waxed paper and sprinkled with semolina. Melt the butter in a large skillet over medium-high heat and cook until it begins to foam and brown, about 4 minutes. Add the sage, salt and pepper. Bring a large pot of water, salted if desired, to a boil over high heat. Add the tortelli and cook until they are tender, about 3 minutes. Toss with the brown butter and Parmesan and serve immediately.