Preheat your oven to 400°F and position a rack in the center. Cut the acorn squash in half from stem to base and scoop out the seeds. Arrange the squash halves cut-side up on a rimmed baking sheet.

Brush each half with 1 teaspoon of olive oil, then sprinkle with kosher salt and ground black pepper. Roast for about 40 minutes, or until the edges are wrinkled and the flesh is fork-tender. Set aside, and reduce the oven temperature to 375°F.

While the squash roasts, heat ½ tablespoon of olive oil in a large skillet over medium-high heat. Add the sausage and cook for about 3 minutes, breaking it into small pieces as it browns.

Next, stir in the chopped mushrooms, onion, and apple, followed by the salt, pepper, nutmeg, allspice, and garlic. Cook everything together for about 8 minutes, or until the sausage is fully cooked, and the vegetables and apple are tender. Let any liquid cook off for the best flavor.

Once the roasted squash is cool enough to handle, carefully scoop out some of the flesh, leaving about a ¼-inch-thick shell.

Add the scooped flesh directly to the skillet with the sausage mixture. Stir in the fresh herbs and ¼ cup of Parmesan cheese. Taste the filling and adjust the seasoning if needed.

Fill each squash half generously with the sausage mixture, mounding it slightly. Sprinkle the remaining Parmesan cheese over the top.

Return the stuffed squash to the oven and bake at 375°F for about 15 minutes, or until the cheese is melted and the filling is hot. Garnish with additional fresh herbs before serving.