Mix the saffron and the hot water and let it sit there for 5-10 minutes to soften and color the water.
Meanwhile, mix together all the other ingredients and taste and adjust for sweetness. The first thing you taste should be sweet. The tang of the yogurt should be the end taste, not the first taste.
Pour in the softened saffron and the water and mix again. Mash up that saffron well to extract flavor and color.
Refrigerate but stir from time to time, to get as much flavor and color as you can from the saffron. You'll notice that each time you stir, it yields a little more color. Don't need to be compulsive about this, just whenever you remember, give it a stir. Once your dessert has a lovely light orange-yellow hue, it's done.