In a separate pot, keep vegetable broth warm.
In a large pan, add Arborio rice, stirring continuously to lightly toast the rice.
Add a ladle of warm vegetable broth to the rice, stirring constantly until the liquid is mostly absorbed.
Continue this process, adding broth one ladle at a time, allowing each addition to be absorbed before adding the next, until the rice is cooked al dente, about 18-20 minutes.
Add pumpkin purée few minutes before end and stir.