I'm not a huge fan of veggie sausages but I recently found that Trader Joe's makes a mean italian version that is pretty darn tasty. If you don't prefer to use veggie sausages, you can always substitute zucchini instead.
You will need:
2 acorn squash, halved
1 onion, chopped
2 ribs of celery, chopped
2 sausages, sliced into half moons
1 large apple, chopped
butter or alternative
salt and pepper to taste
Saute the ingredients (except the acorn squash) in a bit of olive oil, until the onion is soft. Brush the tops and insides of the acorn squash with olive oil and then fill them with the apple/veggie mix. Top each with a small pat of butter.
Bake at 375 for an 75 minutes, or until the squash is soft.