In a small food processor blend the egg yolk, salt, mustard powder, raw apple cider vinegar.
Then slowly pour in the olive oil in a small steady stream and you will see it emulsify. This will take about 1-2 minutes.
Once you have added all the oil then pull apart your probiotic capsule and pour in and let it mix for a further few seconds. Do the same with the lemon juice.
Pour into a sterilised jar and leave outside the fridge for a day.
After that store in the fridge and it will last for about 4 days.
Notes
Feel free to use another oil you like - I have tried it with avocado oil but olive oil is my favourite. Other good oil choices are hemp oil and organ oil and ideally make them organic.