Here’s the thing about custard, at it’s most basic level it is only 4 ingredients, all of which can be safely brought to a powder texture. The food safety danger-zone is 4-60 degrees Celsius and my dehydrator can run at 70 degrees, therefore it stands to reason that custard powder can be made safely (and more deliciously) at home. I do store mine in the fridge though, more because I store my jam there too and it’s sort of a constant reminder to make jam drop biscuits.
480ml full cream milk (it is fine to use milk powder)
6 egg yolks (make omelette or scramble or quiche with the whites. I tried to make nougat and destroyed the kitchen. While this was technically my failing I would not wish that gooey mess on anyone else).
150g small granule sugar (I use brown because I like the flavour, but caster sugar is a more typical choice.)
3 Tbsp corn flour
1 Tbsp vanilla powder (or essence, or vanilla pod)
Gently warm the milk and vanilla powder at a low temperature until slightly foamy around the edges.
meanwhile mix the sugar, corn flour, and eggs into a paste. Do not mix this paste too soon before the milk is ready as it can become gluey (this can be fixed with vigorous whisking or a sieve so do not panic).
Ladle half the warm milk into the egg mixture, whisking well between each spoonful (I use a silicon bottomed mixing bowl, but a wet towel under your bowl will stop it from slipping around so you can ladle and stir simultaneously).
Add the milk and egg mixture back into the milk and vanilla mixture agitating the milk and egg mixture gently with the whisk as you pour (this will prevent mishap with the corn flour).
Bring to a medium heat and whisk continuously until thick
Remove from heat promptly when thick and transfer immediately to baking paper lined drying mats (I use reusable baking paper, but regular baking paper works fine).
Dry at 70 degrees for 12 hours. Mixture should be completely dry, if there are any tacky bits run the dehydrator for longer.
Blitz in a food processor until powdered and use in baking or add to oats for a delicious breakfast out bush.
To rehydrate to custard add 1 part custard to 2 parts hot water and allow to stand for 20 minutes, stirring occasionally. Can also be rehydrated at a gentle boil with constant stirring, but this is less easily achieved when camping. If you hike with butter or ghee then you can gradually add small knobs to warm custard to make a very creamy treat. If you are rehydrating at home then adding heavy cream and butter will make for a very creamy custard. Personally I just eat it as a simple custard or sprinkle it over ice cream still in powder form.