Take a sauce pan or boiler and pour 1 tbsp agar agar powder in 3 cups milk.Let it sit for 1/2 hr.
Meanwhile dissolve 2 tbsp custard powder in 1/2 cup milk and set aside.
When the agar agar is fully dissolved in milk, add sugar and custard powder milk concentrate to the boiler.
Keep the heat on medium low and keep stirring till the custard milk thickens.
Make sure that you do not bring it to a boil at all. It needs to be warm.
To check the doneness of the Pana Cotta, dip the back of a spoon in the concentrate. It should stick at the bottom of the spoon and not runny.
Take 4-6 small bowls and grease them lightly with butter and then wipe off with paper napkin.
Pour the panna cotta mix equally in the bowls. Refrigerate for at least 4 hrs before serving.
When ready to serve, take the bowls out. Keep 4-6 dessert plates ready.
Run a knife around the edges to loosen it up. Place the plate on top of the bowl and flip it gently to place the panna cotta on plate, in the center. If it does't come out in first go, then run the knife till the bottom of the set pudding and try again.
Serve it chilled with the cold Saffron sauce drizzled over it.