Heat the oil in a big pot over medium heat. Add the onion and cook, stirring occasionally, until they are soft and transparent, about 5 minutes. Add the rice and stir to cover in oil, continue cooking for 1 minutes, stir frequently. Add the broth, pumpkin puree, garlic, bay lead and rosemary. Mix until everything is well combined. Season with salt and pepper to taste. Once it boils, cover, reduce to low and cook, stirring occasionally until the water evaporates and the rice is soft and creamy, about 20-25 minutes.