Collect together your equipment (see Recipe Notes below) and ingredients.

Make the orange sauce: use a sharp knife or potato peeler to finely peel the top layer of rind from one orange. Finely shred it. Alternatively, use a zester.

Place in a saucepan, cover with boiling water and blanch for 5 minutes. Drain and dry on kitchen paper.

Finely grate the zest from the other orange. Set aside.

Now, remove the orange segments from the oranges. To do this, use a sharp knife to slice the base from the orange. Place the flat base on a chopping board, steady the top of the orange with one hand and using the other, use firm downward strokes, to slice the skin and pith from the orange. Remove any remaining white pith and then remove the top of the orange.

Hold the orange in one hand over a bowl, to collect the juices, and very carefully cut between the membranes to remove the segments of orange. Place the segments into the bowl with any juice, whilst you make the rest of the sauce.

Boil the sugar and water in a pan until it caramelises and turns a light, golden brown.

Add the sherry vinegar, orange juice, shallots and chicken stock.

Bring to a simmer and reduce to roughly 250ml. Periodically skim off any impurities which rise to the surface of the sauce.

Now add the cold butter and grated orange zest, shake the pan until incorporated and add the orange segments. Continue to warm until heated through but do not boil.

If you want to prepare ahead of time, the sauce can be made until this point and warmed up before you serve.

Make the celeriac and potato purée: peel the potatoes and chop into chunks, roughly the same size. Place in a saucepan and cover with cold water. Bring to the boil, add the salt and simmer gently for 5 minutes.

As the potatoes start to cook, peel the celeriac and chop into similar size chunks as the potatoes.

When the potatoes have been cooking for 5 minutes, add the celeriac, bring back to a simmer, and cook until the potatoes and celeriac are both soft and cooked through.

Drain well, using a sieve or colander, and leave to steam dry for a few minutes.

Put them back in the pan and add the butter and some cream or milk. Mash with a potato masher, an electric whisk or a potato mouli until smooth.

Add extra milk/cream, as necessary. Adjust seasoning, to taste.

When you are ready to serve, cook the duck: score the skin on each duck breast and season generously with sea salt. Try not to cut the flesh underneath the skin, but don’t worry if you do!

Place the duck breasts, skin side down, in a cold pan. Turn the heat to moderately high and cook for around 10 – 15 minutes, or until the fat has rendered. Remove some of the excess fat as they cook. Then, turn the heat to high and cook for a further 2 minutes, or until the skin is caramelised and crispy.

Turn the breasts over and cook for a further 3 – 4 minutes, or until the duck is cooked to your liking.

Hold the duck breasts with tongs and cook the edges in the hot fat, to make sure they are sealed.

Remove the excess fat from the pan, either by pouring it out or carefully absorbing it with kitchen paper. Pour in the Grand Marnier, shake the pan, and carefully set alight to flambé. (NB It is very important to pour out the extra fat, or you will literally have a bonfire when you ignite the alcohol!)

Set the duck breasts aside, on a warmed plate, for 5 minutes to rest. In order to ensure that the duck skin remains crispy, do not cover the plate. Pour any juices, from the pan, or any that collect on the plate as they rest, into the orange sauce.

Now serve this amazing dish: if using the macadamia nuts, heat a pan over a moderate heat and cook them for a few minutes, until lightly browned.

Make a bed of Celeriac and Potato Purée on each plate. Remaining purée can be served separately.

Slice the rested duck breasts and lay over the Celeriac and Potato Purée.

Pour over some hot orange sauce and divide the orange segments between the plates. Serve the remaining sauce separately.

Scatter over some of the shredded orange zest, lambs lettuce or sweet pea shoots and the macadamia nuts, if using. Serve whilst hot.

Delicious with some green vegetables, such as broccoli and/or green beans, on the side.