In a small bowl, add 2 tbsp of water. Place it in the microwave for 90 seconds . Carefully remove it from the microwave and add a generous pinch of saffron threads. Set aside to bloom.
In a saucepan, sauté onion in butter or oil until translucent.
Stir in Arborio rice and toast for 1–2 minutes until edges look translucent.
Add wine and stir until mostly absorbed.
Add bloomed saffron (with liquid) and start adding warm stock 1 ladle at a time, stirring frequently.
Continue adding stock and stirring for 18–20 minutes until rice is al dente and creamy. I tend to add closer to 6 cups of stock just because I like it creamier.
Remove from heat. Stir in Parmesan and butter. Season with salt.