To prepare the squash
Halve the squash lengthwise, remove the seeds. Scoop out the flesh using a melon baller, leaving a border of approx. 1 cm. Salt the squash halves. Finely chop the squash flesh.
Heat the oil in a frying pan. Fry the sausage meat for approx. 5 mins., remove. Sauté the onion in the same pan. Add the squash flesh and cook for approx. 5 mins. Add the spinach, allow to wilt. Add the stock and crème fraîche, simmer for approx. 5 mins., return the sausage meat to the pan, season. Spoon the filling into the squash halves, place the squash on a baking tray lined with baking paper.
Approx. 30 mins. in the lower half of an oven preheated to 200°C. Remove from the oven, sprinkle the cheese on top, cook for a further 15 mins.