Preheat the oven to 400°F / 200°C (180°C fan-assisted) and line a baking sheet with parchment paper.

Lightly brush the squash halves with olive oil, then season with salt and pepper. Place them cut-side down on the prepared baking sheet.

Cook in the preheated oven for 20 minutes, then flip the halves and continue baking for another 20-30 minutes, or until the squash is fork-tender.

While the squash bakes, heat olive oil in a large, deep skillet over medium heat. Add chopped onion and garlic, sautéing until soft and translucent, about 8-10 minutes.

Increase the heat slightly, add the sausage, and cook for about 5 minutes, breaking up the meat with a wooden spoon.

Pour in the white wine and let it cook down until mostly evaporated, about 3-4 minutes.

Incorporate the cherry tomatoes and the sprig of rosemary. Season with salt and pepper, then bring the mixture to a simmer. Reduce heat to low and let the filling simmer gently, stirring occasionally, until the squash is ready.

Remove the baked squash from the oven and allow it to cool slightly. Scoop out most of the flesh, leaving a 1.5-2 cm border to keep its shape. Dice the scooped flesh and stir it into the sausage mixture. Discard the rosemary sprig.

Heap the sausage mixture into the hollowed-out squash halves, creating a mound if there is extra filling. Sprinkle Parmesan cheese over the filling. Return the stuffed squash to the oven and bake for an additional 5 minutes, or until the cheese is melted.

Transfer the stuffed squash to a serving platter and serve immediately. Enjoy!