Place the acorn squash, cut side down on a well oiled baking sheet.
Bake for about 30 minutes, or until 'fork' tender.
Remove from the oven, and let cool for a few minutes.
Scoop out the roasted squash from the skins and set aside.
In a heavy saucepan, heat the olive oil on medium heat, and sauté the onion and garlic for 3 minutes.
Add the curry, spices, and uncooked Arborio rice and stir well, until the rice is coated.
Stir and cook for about 5 minutes.
Combine the water and vegetable broth.
Add the sherry, and 1 cup of the broth, and bring to a boil.
Reduce heat and simmer uncovered, stirring frequently for 7-8 minutes.
When most of the liquid is absorbed, add the remaining cups of broth 1 cup at a time, stirring and simmering until each cup of liquid is absorbed before adding the next one. (The whole process should take about 20-25 minutes.).
When the final cup of liquid is mostly absorbed, add in the roasted squash and mix well.
Continue stirring with a wooden spoon until the rice is creamy, yet still retains some bite.
Add freshly ground pepper, cover and set aside for a few moments before serving.