Preheat the oven to 400°F.
Place the acorn squash cut side up in a baking dish.
Drizzle the olive oil over the squash, season with the salt and pepper.
Place in the oven and roast for 40-50 minutes, until fork-tender.
While the squash is roasting, make the stuffing by sauteing the onion, bell pepper, rosemary, thyme, and sage in 1 tablespoon of the butter in a large skillet over medium-low heat.
Cook, stirring occasionally until the onion and peppers are softened, about 5 minutes.
Add the sausage and garlic, brown the sausage, breaking it up until cooked through.
Reserve 3 tablespoons of the crushed butter crackers for later, add the remaining crackers to the sausage mixture.
Reserve 2 tablespoons of the parmesan for later, add the remaining cheese to the sausage mixture.
Mix the stuffing until combined and take off the heat, set aside.
In a small microwaveable bowl melt the remaining 1 tablespoon of butter.
Mix the melted butter with the leftover crackers and parmesan, set aside.
Once the squash is done roasting, evenly distribute the stuffing into the cavity of each acorn squash half.
Sprinkle the cracker mixture over each of the squash halves.
Bake an additional 10 minutes to brown the topping.
Let cool slightly and serve with a parsley garnish, optional.