1. Preheat oven to 170 c or (340 f).
2. Grease the ramakin dishes with margarine and put aside until needed.
3. Place the meat stock in a pan and bring to a boil.
4. Add the leeks, celery and carrots, reduce heat, cover and simmer for about 3 - 5 minutes.
5. Transfer the vegetable mixture to a bowl and cool slightly.
6. Mix the cream and eggs together, then add them to the vegetable mixture, season with parsley, nutmeg, salt and pepper.
7. Divide the mixture into 6 ramakin dishes and seal with foil.
8. To bake: stand the 6 dishes on a cloth in a baking tin. Fill the tin with boiling.
9. water to 2/3 the height of the dishes and set the tin in the middle of baking sheet.
10. Bake for approximately 40 minutes on a low rack in the oven. The custard should give slightly when pressed with a finger.
11. Remove baking tin, take dishes out of water let stand for 5 minutes, them remove foil and cool slightly.
12. When serving carefully loosen custard around sides with the point of a knife.
13. Turn out onto plates and garnish with halved bacon slices.