In a cup or small bowl with a wide rim, soften the gelatin in the vanilla and Disaronno.
Separate the eggs in a separate bowl and add to the yolks the cream and cornstarch.
Place 4 1/2 cups milk in a saucepan. Add the sucanat and sea salt. Heat until scalding.
Temper the egg yolk mixture by adding a bit of the scalding milk into the bowl, stirring it diligently to be sure it doesn't curdle the egg. Add it back into the saucepan and continue to stir until it develops a texture.
The custard will be ready to take off the heat when you can perform the spoon test. When custard has thickened enough you can dip a spoon in and it will stick to the back of the spoon. You want the custard to look like wet glue on the back of your spoon. If you pull out the spoon and run a clean finger in a line across the back and the custard keeps to itself on either side of your line then the consistency is right.
Getting the consistency right is the difficult part of custard but with the addition of the cornstarch this becomes much easier. See the note on troubleshooting custard.
Once the consistency is right get it off of the heat, pour in the gelatin mixture, and continue stirring until you feel it will not curdle and the gelatin has been thoroughly incorporated.
For refrigerated custard: Pour the custard into serving dishes or a large serving bowl and chill until ready to eat. The time necessary for chilling will depend on what container(s) you store the custard in. For frozen custard (without an ice cream churn): Pour into ice trays and freeze. When you are ready to eat it, put it in a blender with as little milk as you can get away with and blend. If you want chocolate just add a tablespoon of cocoa powder to the blender.