Step 1

In a large skillet, cook sausage over medium-high heat until brown, using a wooden spoon to break up sausage as it cooks. Stir in spinach; cook and stir until wilted. Drain off fat. If mixture is too coarse to stuff ravioli, transfer to a food processor or blender; cover and process or blend with several on/off pulses until chopped.

Step 2

In a medium bowl, combine egg yolk, ricotta cheese, sage, and nutmeg. Stir in sausage mixture. Cover and chill until needed.