Preheat oven to 400ºF.  Cut squash in half and scoop out seeds. Place cut side down on a baking sheet and bake 30-60 minutes, until tender when pierced with a knife (cooking time will vary depending on type and size of squash).

Use a serrated knife to slice the top off of the head of garlic, exposing the cloves inside.  Drizzle 1 tbsp olive oil over top, then wrap up in a large square of parchment paper or aluminum foil.  Roast on pan alongside squash for about 40 minutes, until golden brown and tender.

While squash and garlic are cooling, roll one sheet of puff pastry into a square of roughly 11" x 11".  Position on a parchment-lined baking sheet and brush with remaining tablespoon of olive oil.

When cool enough to handle, peel and mash both the squash and the garlic.  Transfer 1 1/2 cups squash plus garlic to a medium bowl and add 1 tsp kosher salt.  Stir until well combined. Taste and add more salt as desired.

Spread squash mixture over puff pastry, then top with crumbled goat cheese and drizzle with more olive oil.  Sprinkle with a pinch of salt. Bake for 15-20 minutes, or until crust is golden and puffed.  Shower with snipped chives and a dusting of Aleppo pepper, if desired.  Serve warm.