Stuffed Pork Loin recipe

This is one my favorite recipes, but I usually reserve it for the holidays. Prep time is about 30 - 45 minutes and the juices make a wonderful au jus or it works equally well as the liquid in a flour gravy.

1 pound mild Italian sausage (casings removed)
Grannie Smith apple
Walnuts
Fresh parsley
White onion
Salt
Black Pepper
Garlic powder
Olive Oil
3 to 4 pound pork loin

Lightly toast about 1/2 - 3/4 cup of walnuts and chop into small pieces (I used a handful)
Chop about 1/4 cup of fresh parsley (I used just over a rounded palm full)
Peel and dice the apple into 1/4 inch pieces.
Lightly brown and break up the sausage with a bit of olive oil.
Add the apples, walnuts, and most of the parsley to the sausage (save some for garnish).
Add salt, pepper, garlic powder to taste (note this mixture will provide the seasoning for the inside of the loin, so, the mixture should not be bland)
Mix gently so the apples don't fall apart.
Turn off the heat.
Cover the skillet and let it sit for about 3 minutes (stir if you'd like).
Set the mixture aside so it can cool (refrigerator is okay).

Rinse and pat dry the pork loin.

With a long, sharp knife make an incision through center of the length of the pork loin. Being careful not to pierce a hole through the side of the pork loin (juice will leak out), use the knife blade to expand the opening about 1 1/2 to 2 1/2 inches for the full length of the loin.

Retrieve sausage mixture. (Do not use it until it has cooled to at least room temperature!)
Use your hands or a spoon to stuff the mixture into the loin.
Massage the loin to spread the stuffing and get a uniform size for baking (don't want it looking like a pig in a python).

Liberally line a broiler pan or dish with foil.
Spread a light coating of olive oil the foil.
Place the pork loin into the pan.
Rub the outside of the pork loin with olive oil.
Season with salt/pepper/garlic power.

Slice the onion and cover the top of the loin and stuffing.
Use the remainder of the onion and it place around the bottom of the pork loin.
Add 1/4 cup of water to the pan.
Use another sheet of foil to tent and cover the pork loin by sealing the edges of the foil sheets.
Bake at 400 degrees for about 1 1/2 to 1 3/4 hours.
Remove the tenting and cook for an additional 15-20 minutes to brown the top.

Remove the loin to a cutting board and let the meat rest for 15 minutes before slicing.
Reserve the juices from the meat to make gravy.
Garnish with parsley (if you have any left from earlier).