On a commercial machine with a hot water spout I pour about 4 oz into a cup then grind/dose/tamp. The theory is that then the cup will have dropped the temp of the water down below the point where the coffee will burn on contact. Then pour the shot.
So with the Gaggia boil the kettle leave it for a touch before pouring into the cup then prep your shot and pour.
Rough guide anyway* :)