1. Peel the squash, remove the seeds, and cut it into 1/2-inch pieces (about 3 cups). Reserve 1 cup of the squash. Steam the remaining 2 cups until tender, then puree in a food processor.2. In a large, heavy saucepan, heat the oil and 1 tbsp of butter over medium heat. Add the leek and cook for 2 minutes. Add the reserved 1 cup of raw squash and cook for 2 minutes, stirring occasionally. Stir in the rice and cook for 2 minutes. Add the wine and cook, stirring, until it is completely absorbed.3. Add 1/2 cup of broth and cook, stirring, until the liquid is absorbed. Continue adding the broth, 1/2 cup at a time, stirring constantly. Each time the liquid is absorbed, add another 1/2 cup, stirring constantly.4. When the rice is almost cooked (after about 20 minutes), stir in the sage and squash puree. Add more broth if needed and stir until the rice is creamy but still firm to the bite.5. Remove from heat. Stir in the cheese, butter, salt, and pepper.