In a saucepan, warm up the vegetable broth. As it reaches a light simmer, reduce the heat to low. Keep it there throughout the cooking process, as the broth is added to the risotto as it cooks, and you don't want to lower its temperature by adding cold stock, as this cooks the grains unevenly.

Add the saffron powder or pistils to a small bowl and add 3-4 tablespoons of hot broth to it.

In a large or medium saucepan with a heavy bottom or Dutch oven, heat the olive oil on low to medium heat.

Add the thinly diced onions, season them with a pinch of salt and pepper, and cook until they become transparent. This will take approximately 3 minutes.

Next, add the sliced mushrooms and mix well. Cover the pan with a lid and allow the mushrooms to cook for about five minutes. This will allow them to release their flavor into the pan.

Remove the lid, allow the excess liquid to evaporate for about 30 seconds, then add the rice.

Stir the rice continuously to ensure even toasting and prevent it from sticking to the pan. You want the rice grains to become slightly translucent around the edges.

Once done, start incorporating the broth a ladle at a time, adding more when required. Allow the rice to absorb most of the broth before adding the next ladleful. You'll notice the risotto becoming creamier as you add more broth and stir.

Stir the mushroom risotto every couple of minutes and add broth to the pan until the risotto is cooked. Cooking the risotto while adding the broth will take approximately 18-20 minutes.

When the rice is nearly cooked [about 13-15 minutes since you started adding the broth], add the cup of saffron-flavored stock. Mix well, and continue cooking the rice as you were.

Once the risotto with saffron and mushroom is ready, remove it from the heat, add the freshly grated Parmesan cheese and the butter, and mix well.

Allow the rice to rest for a couple of minutes before serving, and enjoy it still hot with an extra sprinkle of grated cheese or a little fresh parsley on top and a side salad or protein.