Bring 7 cups water and rice to boil in heavy large saucepan. Reduce heat; cover and simmer until rice is tender, about 1 hour. Drain. Transfer rice to large bowl.
Preheat oven to 375 degrees F. Oil baking sheet. Place squash cut side down on sheet. Bake until tender, about 40 minutes. Cool. Using spoon, scoop out pulp from squash, leaving 1/4- inch thick shell.; reserve shells. Transfer pulp to medium bowl. Reduce oven temperature to 350 degrees F.
Melt butter in large nonstick skillet over medium heat. Add onions, saute until very tender, about 15 minutes. Add sage; stir 2 minutes. Add rice, squash pulp, lemon juice, ; stir until mixed, breaking up squash pulp into smaller pieces. Mix in 1/2 cup cranberries, 1/2 cup hazelnuts and parsley. Season with salt and pepper.
Divide rice mixture among reserved squash shells. Place in roasting pan. (Can be made 6 hours ahead. Cover and chill.)
Bake squash until filling is heated through, about 25 minutes. Sprinkle with remaining 3 tablespoons cranberries and 3 tablespoons hazelnuts.
Full recipe title: Acorn Squash Stuffed with Wild Rice, Hazelnuts and Dried Cranberries