Preheat the oven to 180°C (Gas mark 4/350°F). Lightly oil a small roasting tin (check that it is large enough to hold your 6 mini pumpkins).
Prepare the pumpkins. Scrub the outside of the pumpkins well under running water and pat dry. Slice the top off each pumpkin, as you would when carving a full-sized pumpkin, and set to one side.
With a spoon, scoop out the seeds and pulp from inside each pumpkin, taking care not to remove too much of the flesh.
Next, prepare the sausage stuffing. Peel and finely slice the onion and place in a bowl.
Remove the sausages from their skins - I find that the easiest way to do this is to slit the skins down the length of the sausage with the tip of sharp knife, then peel it back from the sausage meat to remove.
Discard the skins and add the sausage meat to the bowl with the onions, along with the bread crumbs, dried sage and a splash of water. Season with salt & pepper if wanted.
Mix the stuffing ingredients well until completely combined.
Place the hollowed out pumpkins into the oiled roasting tin, then spoon the stuffing mixture into the pumpkins, splitting the mixture between all six. Depending on the size of your pumpkins, you should have enough to just fill them all.
Pop the 'lids' back on the pumpkins, then place in the oven and roast for 30 minutes.
After 30 minutes, remove the tops from the pumpkins and pop on a plate to one side. Return the pumpkins to the oven and roast for a further 10-15 minutes. The pumpkins are done when the pumpkin is cooked through (test for softness with the tip of a sharp knife in the side of a pumpkin) and the stuffing is starting to crisp up on top.
Pop the tops back on the pumpkins to serve.