Drizzle some olive oil in a large pan, then add the finely chopped onion and the rice. Turn on the heat and toast the rice for 1-3 minutes (be careful not to burn the onion).
Pour the white wine and let it evaporate, then add a part of vegetable broth. Bring again to boil then turn the heat to low and let it simmer, mixing with a wooden spoon once in a while.
Every time that the broth is absorbed by the rice, add a little bit more. Continue until the rice is cooked al dente (about 20 minutes).
Halfway through the cooking, add the pumpkin purèe, the thyme, and some salt. Continue cooking adding more broth when necessary.
When the rice is cooked al dente, turn off the heat, add the butter and Parmigiano cheese and mix well. At this point, the risotto should be creamy. Season to taste then serve in bowls and add the Gorgonzola cheese on top.
Notes
Risotto should be eaten immediately as otherwise, it will become overcooked and too soft. Although, if you have leftovers, you can store them in an airtight container in the fridge for 3 days.If instead, you want to creatively reuse the leftover risotto, you can turn it into Arancini.