01 - Preheat oven to 400°F. Toss diced pumpkin with 1 tablespoon olive oil, salt, and pepper. Spread on a baking tray and roast for 25 to 30 minutes, turning once, until golden and tender.
02 - Heat remaining olive oil and half the butter in a large heavy-based saucepan over medium heat. Add chopped onion and cook for 3 to 4 minutes until softened. Stir in minced garlic and chopped sage; cook for 1 minute.
03 - Add Arborio rice and stir continuously for 2 minutes until grains are well coated and slightly translucent.
04 - Pour in the white wine and cook, stirring, until mostly absorbed by the rice.
05 - Add warm vegetable stock one ladleful at a time, stirring frequently and allowing each addition to absorb before adding the next. Continue for 18 to 20 minutes until rice is creamy and al dente.
06 - Fold in roasted pumpkin and cook for an additional 2 to 3 minutes to heat through.
07 - Remove from heat. Stir in remaining butter and grated Parmesan. Season with salt and freshly ground black pepper to taste.
08 - Plate immediately, garnished with extra sage leaves and Parmesan cheese.