Preheat your oven to 400 degrees and line a baking sheet with tin foil.
Cut the squash in half lengthwise and scoop out the seeds. Place it cut side down on the baking sheet and place in the oven for 30 minutes.
While the squash is cooking, heat a large pan over medium heat.
Add the bacon and cook until crispy. Remove with a slotted spoon and place on a paper towel lined plate.
When the squash has 10 minutes left to cook, add brussels sprouts, onion/leek and apple cider vinegar to the rendered bacon fat in the pan over medium heat. Sprinkle with salt and pepper and garlic powder. Cook down, stirring every couple minutes.
After 5 minutes, add in the mushrooms, bacon and sausage. Cook down for about 5 minutes, until sausage is hot.
Remove the squash from the oven, fill it up with the brussels mixture and serve.