Remove the stems of the squash. Then hollow them out. I recommend cutting a circle around the top, and then using a spoon to scrape the middle out. Try to save as much of the meat as you can, removing the handful of seeds in the middle. Chop squash that you saved and set aside.
If your sausage is in links, cut it open and remove the skin. Add the butter to a large pan on medium heat. Add the sausage and break it apart as it cooks.
After a minute, add the squash, parsley, and garlic.
After another 2 minutes, add the bread and stir thoroughly to get the grease all over the chunks of bread. Your sausage should not be cooked all the way through; it still has plenty of time in the oven!
Stuff the squash shells with the stuffing and place them in a rimmed pan. If it doesn’t all fit, you can add the extra to the pan too. Bake for about 30 minutes, or until the squash is soft and the sausage is cooked through.