Preheat oven to 350°F / 177°C / Gas Mark 4
Cut squashes in half and scoop out seeds. (Reserve seeds for roasting, if desired)
Drizzle a tablespoon of olive oil over the inside of the squash halves and season with half of the salt and pepper.
Roast, cut side down, for 30 minutes.
While squash is in the oven, start the filling: In a large sauté pan, cook the sausage (if using ground pork, see note below).
When sausage is no longer pink, add apples and onions to the pan. Season with remaining salt and pepper.
Cook for 7 - 8 minutes, until onions are translucent and softened.
Add cooked rice and pecans to the pan and stir to combine.
Cook filling for 5 - 6 minutes over medium low heat, then set aside to cool.
Remove squash from oven, carefully flip over, (steam will escape from under the squash) and let cool for a few minutes.
Fill squash, evenly dividing the filling between the 4 halves, cover with foil and bake for an additional 15 minutes.
Remove foil and bake uncovered for 5 more minutes to give the top a bit of color. Garnish with herbs, if desired.