Prepare the filling.
Finely dice the onion and garlic.
Place on a pan greased with ghee and cook over a medium-high heat for a few minutes, until fragrant.
Remove the sausage casing and place the sausage meat in the pan with onion and garlic.
Break into smaller pieces with a spatula.
Cook until the meat is browned from all sides.
This will take just 6-8 minutes.
Then, use a slotted spoon and transfer the meat in large mixing bowl.
Add the sage and flaxmeal and season with salt and pepper to taste.
Set aside and preheat the oven to 190 °C/ 375 °F.
Prepare the tenderloin (also known as pork fillet in the UK as opposed to pork loin which is much bigger).
Cut the tenderloin lenghtwise almost all the way through leaving out about 1/2 inch (1 cm) so you can then open the tenderloin like a book.
Cover the tenderloin with a piece of cling film and evenly pound the meat with a meat tenderiser/ mallet until about 1/2 inch (1 cm) thin.
When done, set aside.
Prepare the "bacon net".
Lay 7 thin stripes of bacon on a chopping board.
Then lay the remaining half of the bacon strips over in an alternating order ...
...
to create a bacon net.
Put the pounded tenderloin over the bacon net and place the sausage stuffing in the middle so you can tightly roll it up lenghtwise.
Move the rolled tenderloin to the edge of the bacon net and roll it to wrap it round the tenderloin (be careful not to spill the filling).
Secure the edges of the tenderloin with two toothpicks on each side so the sausage stuffing stays inside.
Place the tenderloin on a rack or baking sheet seam side down.
Bake for 35-45 minutes or until your meat thermometer reads 63-68 °C/ 145-155 °F depending on how well done you like it to be.
If the bacon is not crisped up enough, place under a broiler for a few minutes.
Remove the toothpicks.
Try with Ultimate Keto Gravy or Keto Cheese Sauce, crispy greens or Keto Cauli-Mash.