Combine the turkey, pork fatback, sage, garlic, chives, pepper, nutmeg, orange zest and 2 tablespoons salt in a large bowl. Transfer to a large plastic zip-top bag and refrigerate overnight.
At least 30 minutes before grinding the meat, place all of your tools (including the meat grinder parts, stand mixer bowl, stand mixer paddle attachment and sausage stuffer parts) in the freezer to chill.
Using your meat grinder, grind the marinated meat mixture through the small die plate into the chilled bowl of the stand mixer. Refrigerate at least 30 minutes, then return the mixture to the mixer. Add the milk and wine and beat on medium speed using the chilled paddle attachment until combined. Refrigerate until ready to use.
Stuff the sausages (see Cook's Note) and, for best results, refrigerate overnight.
Before cooking, pierce each sausage several times with a pin. Grill over medium heat until the center registers 160 degrees F, 10 to 12 minutes. (You can also pan-fry or broil the sausages.) Serve in split toasted buns with spicy brown mustard and grilled red onions.
Photograph by Kat Teutsch
How to Stuff Sausage: 1. Spoon the sausage mixture into the stuffer's canister and lightly oil the outside of the nozzle. Thread a hog casing onto the nozzle, pushing it all the way back so the casing bunches at the base of the nozzle. 2. Pull about 3 inches of casing out from the nozzle. Crank the handle to push about 1 inch of the ground meat mixture into the casing. 3. Press out any air between the meat and the end of the casing and tie off the casing. (Use kitchen twine or make a knot.) Try not to leave any air between the meat and the knot. 4. Crank the handle to push 5 more inches of meat into the casing, pulling the casing gradually so it doesn't get overstuffed. The sausage should have some give to it; press the casing with your thumb ¿ it should leave an indentation. 5. Stop and twist the casing a few times to form a link, then continue pushing meat through and twisting the casing to form 6-inch links. 6. When all of the meat is used, press out any air and tie off the casing at the end. Refrigerate for up to 2 days. You can cook the links joined together or cut them apart.
Recipe courtesy Michael Symon for Food Network Magazine