Start by roughly chopping the bacon lardons and place it in a large bowl with the pork liver. Add the onion, garlic, orange zest, thyme, chopped bay leaves and mix together well. Pass this mixture through a mincer and return it to the bowl. (If you don't have a mixer then you could use a food processor on a low setting, or finely dice the meat by hand.) Add the egg, breadcrumbs and prunes, then season and mix everything together, then set aside.
(This recipe works really well with the addition of caul fat, however it is often quite hard to get hold of it (we don't have it available all the time). You can still make the recipe without the caul fat, just skip the steps that mention the fat.)
Remove the caul fat from the water and lay it out over a large chopping board or clean work surface, overlapping the sheets so they form a surface area large enough to envelop the entire saddle once stuffed. Scatter over the sage leaves randomly, then place 4–5 lengths of butcher’s string, each around 40cm long, over the caul at an even distance apart.
Take the saddle of venison and with a sharp knife cut it open like you would when opening a baguette, you are aiming to 'butterfly' the joint.
Lay the venison on top of the caul and string, skin-side down. Spoon the stuffing down the centre between the two loins, shaping it with your hands into an even sausage form.
Fold in the sides of the venison to encase the stuffing as neatly and evenly as you can. Now bring up the strings and tie them off to secure the rolled meat. Lift the caul over the venison in neat ordered folds. Carefully lift the saddle and turn it over and place in a large roasting tin.
Pre-heat the oven to 200°C fan/390°F/gas mark 6. Place the venison in the oven and roast for 10 minutes, then turn the heat down to 180°C fan/350°F/gas mark 4 and continue to cook for a further 30 minutes, or until a meat thermometer pushed into the joint reaches 60°C, for medium-rare meat.
Remove the venison, cover and allow it to rest for 15 minutes.
Slice the meat and stuffing and serve.
You can find more of Gill Meller's beautiful recipes in his book 'Time: A Year and a Day in the Kitchen'