For the roast you need 5 ingredients:

1 3kg pork leg roast Ask your local butcher to debone the roast and help you remove the skin.

2 Vegetables The classic combination of onion, carrot and celery is called a mirepoix in French and it’s the perfect start to a great gravy. Keep the veggie pieces chunky and use one or all three of the classic trio, depending on what you have in your fridge.

3 Herbs Use a bunch of mixed hardy herbs like thyme, bay leaf, rosemary and parsley stalks – or choose your favourite.

4 30 ml flour A dusting of flour helps the baking bag make its magic; in fact, it’s a good idea no matter what you’re roasting.

5 500ml ginger ale or stock The liquid you choose for the roast flavours the meat and is also the start of your gravy. You could simply use water or take the opportunity to add extra flavour with ginger ale, fruit juice or stock.

1 Preheat the oven to 170°C. Score the fat on the pork with thin cuts and rub with your favourite seasoning. We used coarse salt, black pepper, fennel seed, coriander and cumin. Tie the meat in a neat roll. Brown the pork roast by searing the meat in a pan over high heat.

2 Open the large baking bag and place in a roasting dish. Add the flour, vegetables, browned roast, herbs and cooking liquid. Seal the bag and pierce about 5 times with sharp scissors or a knife. Now roast for about 1 hour/kg of meat. Because the meat is seared before roasting and I love succulent pork, I roasted this beauty for just 2 hours and 30 minutes.

3 Cut open the bag and remove the roast. Cover the meat with foil and allow to rest while you make the gravy.

For the gravy you need 5 more:

1 The strained pan juices from your roast pork The fragrant juices in which the meat roasted will be sweet from the ginger ale and savoury from the spices and vegetables – the perfect start for gravy!

2 A slurry made from 30 ml flour mixed with 125 ml stock Mix the flour with the stock to form a smooth paste. This will help prevent lumps in the final gravy.

3 10ml Dijon mustard Mustard adds warmth and depth of flavour to the gravy.

4 A dash of sweet sherry Why not?

5 A drizzle of cream Cream adds richness and balances the sweet notes in the sauce, which could become overwhelming after reducing.

1 Heat the strained pan juices directly on the stove or decant into a pot.

2 Whisk in the slurry and cook for a couple of minutes until the gravy thickens slightly.

3 Flavour the gravy with the mustard, sherry and salt and pepper to taste. Allow to reduce until the consistency is thick and glossy.

4 Add the cream, whisk through and give your gravy a final taste before straining.

5 Thinly carve the rested roast (when it comes to a drier cut of pork like the leg, it’s best to serve it in thinly carved slices with lots of lovely rich gravy). Arrange on a pretty serving platter with the roasted vegetables from the baking bag and drizzle with gravy. Serve with your favourite sides like roast potatoes or rice.