Preheat the oven to 180C.
Place a heavy based saucepan or casserole dish with a tight fitting lid over medium-low heat. Add the olive oil, onion and garlic, and cook until translucent.
Stir through the thyme leaves and rice. Add the wine (if using) and cook this for another minute, until it evaporates.
Add the pumpkin and the broth, cover with the lid and bake in the oven for 30 minutes. There should still be some excess liquid and the rice should be just cooked. If it isn't, cook for another 4-5 minutes. If it's dried out, add enough hot water or broth to loosen it up.
Stir through the butter, parmesan cheese and lemon zest. Use the spoon to mash/puree some of the pumpkin. Season to taste and garnish with extra parmesan and fresh herbs.