Peel the butternut squash or pumpkin. Bake half in the oven and then puree, and the other half cut into small dice, and sauté in a little oil. In a medium-size heavy saucepan or deep non-stick pan, heat the olive oil over medium-high heat. Add the onion and sauté, stirring continuously, just until softened, 3 to 4 minutes. Add the chopped sausage and cook with the onions for a further 3 minutes. Now add the rice and continue to stir, using a wooden spoon, to coat the rice with the oil and mix with the sausage. Add the white wine and continue cooking, stirring often, until it has been absorbed by the rice. Pour in enough stock to cover the rice completely, about 3 cups, and continue to cook, stirring often, until all the liquid is absorbed. Pour in 1 cup more of the remaining stock and stir and cook until it has been absorbed. Repeat with 1 more cup. Add the remaining cup and cook, stirring, until the rice is al dente, tender but still very chewy, and most of the liquid has been absorbed. Stir in the pumpkin puree, diced pumpkin and peas and reduce the heat to very low so that the risotto doesn’t simmer anymore. Season to taste and stir in the grated Parmesan and butter to give the risotto a nice, creamy finish. Spoon it immediately into serving plates, garnish with fresh chopped parsley and parmesan shavings.