Cut acorn squashes in half, top and bottom halves. Remove stem off top half by scraping with your finger or fingernail. They come right off very easily. Remove seeds with a spoon. You can toss the seeds in the trash or bake them like pumpkin seeds to snack on for later.
Brush olive oil over fleshy half of squash. Place in a baking dish, fleshy half up. Add about 1/4" of water to bottom of baking dish so squashes don't dry out or burn while cooking.
Bake for 1 hour or until squash flesh is soft and lightly browned. Remove from oven. Once cooled, puree the flesh of 1 acorn squash for risotto. Set aside.
Pour vegetable broth into a large sauce pan. Bring to a boil, turn off heat, and cover. Set aside.
In a large skillet, heat olive oil. Add in onions once oil is heated and sauté onions until they are clear.
Stir in rice and sauté until rice is a light brown color.
Add wine with 1 cup of vegetable broth, stirring until liquid is absorbed.
Gradually add in broth, 2 cups at a time, stirring well until almost all the liquid is absorbed in with the rice. Repeat adding broth, 2 cups at a time, until all of it has been added to rice and risotto is creamy.
Stir in acorn squash puree.
Remove pan from heat and add in parmesan cheese, stirring well so all cheese is mixed thoroughly. Salt & pepper to taste.
Spoon risotto into baked acorn squash halves and serve with grated parmesan cheese over the tops.