Step 1Heat the oven to 375 degrees. Place the hazelnuts on a baking sheet and toast them until lightly browned, about 10 minutes. Let cool, then break the toasted hazelnuts in half, using your fingers. Set aside. Reduce the oven temperature to 350 degrees.
Step 2In a large saucepan, combine the rice, onion, parsnip and 2 1/2 teaspoons salt in 1 quart cold water. Bring to a boil, then reduce the heat to a low simmer and cook for 45 minutes to an hour, until the rice grains open and are mostly tender.
Step 3Cut the squash into one-half inch cubes. In a medium pan, saute the squash in 2 tablespoons of the butter over medium heat until they're cooked but not mushy, 7 to 8 minutes.
Step 4Drain the rice and pour it into a large bowl. Remove and discard the parsnip and add the squash, hazelnuts and the seeds from one-half pomegranate, reserving a few seeds for garnish.
Step 5Cut the remaining half pomegranate in half and squeeze the juice over the rice mixture. Add the hazelnut oil, one-fourth teaspoon salt and the pepper, and place the rice in an ovenproof dish. Dot the rice with the remaining butter and warm it in the oven about 15 minutes. Garnish with pomegranate seeds and serve.