Wash the sausage casings thoroughly inside and out in running water, making sure they do not escape down the drain! Fill with tepid water, and leave to soak in the sink while preparing the sausage meat.
Cut all the meat into 1" cubes, ready to mince using small holes.
With the coarse blade in the mincer, pass all the fat through.
Then change the blade to small and mince the lean meat.
Grind the salt, pepper nutmeg sage and thyme in a spice mill until very fine. Mix all together thoroughly, taking care not to beat too vigorously, the meats should be completely homogenized.
Take a small patty and cook it in a frying pan to check the seasoning. Re-season if needed.
Slide the skins onto the filling tube and fit to the mincer. Fill the casings, taking care not to fill too tightly, or the sausages will burst when cooked.
Twist into suitable sized links and hang up in a cool place to mature 24 hours before freezing or cooking.