In a large pot over medium heat drizzle olive oil and use it to cook the onions, thyme, lemon zest and bayleaves. Cook them until they are translucent and smell sweet.
Add the rice and stir for a minute.
Add the white wine and stir until the white wine completely evaporates.
Add 2 ladles of stock (which should be hot ideally) and the butternut squash purée.
Stir constantly until the liquid evaporates and then add more stock. Keep adding 1 ladle of stock at a time and stirring until the rice is cooked al dente. You will have to try it in the process and eat a few raw rice grains but it's worth it!
Finish with the parmesan cheese and butter. Taste and add pepper and more salt if needed.
Assess if you need to add some final ladle of stock. The texture should be such that if you ran a spoon or spatula down the center of the pot the risotto should easily cover the space back up.
Serve immediately and garnish with fresh oregano leaves and extra Parmesan cheese.