I am always interested in trying to cook marinated soft boiled egg myself since I am a big ramen addict. With all my model kits, supplies and tools boxed up now, I have some extra time on hand to kill. And I have been experimenting with cooking soft boiled egg.
If I did not try to make soft boiled egg, I would not know the culinary science behind boiling eggs. Egg yolk and egg white get cooked at different temperatures. While egg white solidify at a lower temperature and egg yolk turns to solid at a slightly higher temperature. So, to cook soft boiled egg the water temperature need to be just right.
What I figured out is to bring the water to simmering first, then take the large size egg from the fridge and lower them gently to the simmering water for about 8 minutes. Then chill them in ice water. Peel the shells off.
The marinate I used is just soy sauce, sugar, rice wine and water. Soak the eggs in a bowl with the marinate and leave it in the fridge overnight.