Preheat the oven to 220c (200c fan-assisted).
Add the onions and roasting herbs around the meat in the roasting tin.
Transfer to the oven. Cook for 30 minutes.
Turn the heat down to 180c (160 fan-assisted) and cook for a further 60 minutes. Baste halfway through cooking.
Remove the meat and allow to rest for at least 15 minutes.
To make the gravy, put the roasting tin back onto the hob on a low-medium heat. Deglaze the pan with about 100ml boiled water using a wooden spoon.
Using a wooden spoon, pass the gravy through a sieve to remove the onions and cooking herbs.
Return to the pan and thicken and heat through with a little cornstarch before transferring to a gravy boat.
Once rested, slice the roast pork and serve with the gravy, apple sauce, roast potatoes and your favourite vegetables.
Tip: To adjust cooking time for different weights, weigh the pre-cooked weight of the roasting joint. Calculate 35 minutes per 500g, plus another 35 minutes. So a 1.5kg joint would take 30 minutes at 220c, plus 1hour and 50 minutes at 160c.