Wash, rinse and put your bottles in a warm oven to dry and sterilise
Sieve the dry ingredients into a large bowl.
Beat the eggs together in a large jug, pour in the milk and oil and whisk to combine
Add the milk mixture to the flour mixture carefully, avoiding lumps if possible
Gradually - and slowly - add the vinegar, stirring all the time
Transfer to a double boiler* and bring the mixture up to a simmer. Stir constantly.
Cook at a simmer for around 20 minutes, stirring all the time, or until the mixture has thickened but still creamy. Cook for a further 5 minutes.
Take from the heat and bottle up immediately, sealing will hot.
The mixture will thicken more on cooling.
Great with salads and as a mix with egg for sandwiches
* I used one preserving pan with the salad cream set over another preserving pan with boiling water in the bottom to about 10cms/4 inches.
Check the water level during cooking time and top up if necessary.