Preheat your oven to 400° and line a baking sheet with parchment paper.
Slice the squash in half and remove the seeds. If it’s difficult to cut in half, place it in the heated oven for about 10 minutes to soften it.
Drizzle a little oil on both halves and sprinkle on some salt and black pepper. Place cut side up on the prepared baking sheet, and roast for 35-45 minutes, or until tender.
Peel most of the paper off of the garlic, but make sure you keep the bulb intact. Use a sharp knife to cut the top part of the garlic bulb off. You’ll want to trim about ¼” off.
Drizzle the tops of exposed cloves with a little oil and sprinkle with salt and black pepper. Cover the bulb with foil and bake for about 40 minutes, until the cloves are soft. The garlic is done with deeply golden brown and completely soft.
If you time it right, the squash and the garlic will be done around the same time. Allow them both to cool slightly, so they’re not too hot to handle.
Scrape the squash out of the skin, and place it in a large bowl. Squeeze the roasted garlic out of the paper into the same bowl and add the vegetable stock. Mash everything together with a potato masher or large fork. You can go as creamy or as lumpy as you like. (I prefer a few lumps.) Taste and season with more salt and pepper, if you like.