Chop the onion into small bits, then cook it in a pan with olive oil until it becomes translucent.

Add the crushed garlic cloves and cook for a minute, then add the Dijon mustard and maple syrup and cook for a further minute. Turn off the heat and set it aside.

Slice the apple thinly, then slice the Brie and open the pork tenderloin fillet creating an incision down the centre.

Fill the tenderloin with the apple slices and the Brie, then layer the onions on top.

Measure a piece of butcher's twine long enough to go around the tenderloin and tie it securely. Cut the twine using scissors. Slide the middle of the twine underneath the pork tenderloin, positioning it where the opening is to be sealed. Bring the ends of the twine up and cross them over the top of the pork tenderloin, ensuring that the twine holds the opening closed. Wrap each end of the twine around the pork tenderloin, pulling tightly to secure the opening. Continue wrapping until you reach the other end. Tie a secure knot over the top of the pork tenderloin, ensuring that the twine is tight enough to keep the stuffing inside. You can use a simple knot or a butcher's knot for extra security.

Use scissors to trim any excess twine, leaving a neat appearance.

In the same pan where you cooked the onions, brown the meat on all sides so that it gets some colour and flavour going.

Move onto a baking tray covered with parchment paper, drizzle with extra olive oil and bake in a preheated oven at 200C for 40-45 minutes.

Remove the butcher's twine and slice to serve with your favourite sides.