I'm not sure why this is "Spanish" as opposed to another version, "Bavarian", which has more cream in it.
- Save a small amount of the milk; put the rest in a saucepan together with the sugar and vanilla, and heat through.
- Separate the egg whites and save for later. Beat the egg yolks with the remainder of the milk and add to the heating mixture.
- Stir to ensure the sugar is dissolved and bring to near boiling point to thoroughly cook the eggs. Do not actually boil.
- Take the saucepan off the heat. Dissolve the gelatine in 60ml of boiling water and stir into the hot custard.
- Pour into a serving dish and put in the fridge to cool.
- When mixture has cooled and almost set (it should be shivery at this point) thoroughly beat the egg whites until stiff and fold them in using a metal spoon.
- Return the mixture to the fridge to set properly.
- This goes well with any poached fruit but nectarines poached with a vanilla pod would be delicious.