Heat up chicken stock into a large pan, and add saffron strands. You want to heat the saffron and the chicken stock together so you get the flavor from the saffron. Saute butternut squash in a large saucepan for a couple of minutes, it will begin to brown, when the squash begins to brown, add the diced onion to the saucepan.
When the onions have become translucent add the rice, and stir to coat the rice with the butter until all of the rice is shiny, and the rice turns white and chalky.
Add one cup of broth at a time until the broth is soaked into the rice. Continue doing so, this should take about 20 to 25 minutes until all of the stock and wine, if used is incorporated.
When all of the stock is incorporated the mixture should be creamy, add cheese, and stir to incorporate, taste rice, and adjust seasoning with salt and pepper. Parmesan cheese tends to be a little salty so don't check for seasoning until the dish almost completed. Let risotto rest for a couple of minutes before serving.