Mix butternut squash, ricotta, Parmesan, and orange zest. Season with salt, pepper, and nutmeg. Brush pasta sheet with beaten egg and cut into 4-inch squares. Spoon squash filling in the middle of pasta square and fold over. Cut excess pasta with round dough cutter into half moon shape. Place on floured tray.
Boil agnolotti in salted water until tender, about 3 to 4 minutes. Drain and place on a platter. Add butter and sage leaves to a medium sized saute pan and place over medium high heat. Cook butter and sage until butter is golden brown. Spoon butter and sage over agnolotti and sprinkle with flaked Parmesan.
Combine dry ingredients in mixer. Combine eggs, egg yolk, and spinach puree, and mix well. Add spinach and egg mixture to dry ingredients on low speed until dough is formed. Remove dough from bowl and kneed by hand for 6 to 8 minutes. Let pasta rest covered for 30 minutes before using. Roll dough into sheets.
Recipe courtesy of Scala's, San Francisco, CA