To bloom saffron, put saffron threads in a small bowl. And add 2 tablespoons of boiling water. Let it to bloom for 10 minutes.
Meanwhile, melt butter in a medium saucepan over medium high heat. (TIP: Make sure your saucepan has a tight-fitting lid. I use 2.5qt saucepan.)
Add rice and cook it for 3-5 minutes, stirring constantly.
Add stock, salt, and bloomed saffron with its water.
Cover and bring it to a boil.
Reduce heat to low and continue to cook until all the liquid is absorbed and rice is fully cooked, about 15 minutes. (NOTE: Don’t open the lid while rice is cooking.)
Carefully fluff it with a wooden spoon, or fork, and serve.