Take out the millefeuille pastry out of the freezer and set aside to soften. Cut/break in the middle to get squares if rectangular shaped. Set aside to soften, but do not place them one on top of the other if you have removed the paper in between them.
Place the cubed meat into the cooking pot, preferably lamb. If not lamb, in preference order these can also be used: beef, turkey, chicken. Cook without adding anything else until the meat first leaves off and then absorbs back its juice. The lid should be closed, you may mix once in a while.
Add two bay leaves if using lamb, take out the leaves and discard after meat is ready.
When the meat is ready add these in sequence, leaving 2 minutes in between. Chopped onions, chopped garlic, first peeled then cubed carrots and peas. Mix well. Add warm water to cover the bottom of the cooking pot. Do not use canned peas as they are too soft. Frozen peas will be fine.
Cook with covered lid, over medium heat, until the water evaporates. It the water is too much, drain. Set aside to cool.
Sprinkle your working space and the top of each millefeuille pastry with some flour. Make the pastry widen about 25 cm/10 inch every side, using a rolling pin. Place 2 tablespoons of filling mixture in the middle and close the pastry like an envelope. Turn upside down and place on a oven tray with an oven sheet.
Spread some egg yolk on the top using an egg brush. Sprinkle some nigella seeds on top.
Cook in a preheated oven at 175° Celsius/ 350° Fahrenhite for about 15-20 minutes, until golden brown on all sides.