Preheat the oven to 400 degrees F, and line a rimmed baking sheet with parchment paper, and set aside until ready to use.

Chop the squash lengthwise in half. Scoop out the seeds and stringy insides.

Season the inside with salt and pepper and place the cut side down onto the prepared baking tray.

Bake for 30 minutes and then turn them around to bake for another 10 minutes, or until squash is fork-tender. The amount of time will depend on the size of the squash.

In the meantime, prepare the filling.

In a 12-inch high-sided skillet, add olive oil and set over medium-high heat.

When the oil is hot add the garlic and sauté until fragrant, about 30 seconds.

Add the roughly chopped fresh spinach and sauté for one minute or until the spinach is tender.

Remove from heat and add shredded mozzarella, softened cream cheese, gorgonzola cheese, and shredded parmesan. Stir to combine until smooth and creamy.

Once the butternut squash is fork-tender, remove from it the oven. Remove a bit of the squash from the shell to create a "bowl" for the filling. This is the same technique you would use for twice-baked potatoes. Don't remove too much squash as you don't want the squash outside to fall in on itself.

Add the removed squash to the cheese mixture and stir to combine.

Fill the squash with the cheese mixture and bake for 10 minutes or until the cheese is evenly melted.