Spray six (4 oz) bavarois molds; set aside. Put the milk, 1 tsp cinnamon and half the sugar in a saucepan and bring it to a boil. In a small bowl, whisk the egg yolks and remaining sugar until light and fluffy. Temper the egg yolks by adding a small amount of the milk to the yolks while whisking, then pour the mixture back into the saucepan. Reduce the heat and cook, stirring, until it is thick enough to coat the back of a wooden spoon. DO NOT LET IT BOIL or the custard will split.
Soak the gelatin leaves in cold water until soft; drain and add to the hot custard along with the vanilla extract. (If using powdered gelatin, sprinkle it on the hot custard, leave it to sponge for a minute, then stir it in) Strain the custard into a clean bowl and cool.
Whip the cream and fold it into the custard. Pour the mixture into the prepared molds. Place in the refrigerator for at least 4 hours, or until set.
Unmold the bavarois by holding each mold in a hot cloth and inverting it on a plate with a quick shake. Dust with the extra cinnamon and serve immediately.