In a saucepan, bring water to a boil. Carefully add four eggs in and cook them for 9 minutes. Once cooked, plunge them into cold water; eggs will be easier to peel.
Peel and roughly chop shallots. Peel and mince garlic clove. Trim the parsley, and chop the leaves coarsely. You want to get a large handful.
Mix the two types of ground meat. Add garlic, shallot, and parsley. Combine.
Add 1 beaten egg, 2 tablespoons of Cognac and 1 heaping tablespoon of flour. Season generously with nutmeg, pepper, and salt. Mix well. Stuffing is done.
Prepare en croute pâté
Roll out the two puff pastries, one for the bottom, the other for the top, which must be larger as it will cover the thickness of the stuffing. Place the bottom pastry on a baking sheet lined with parchment paper.
Pour 1/3 of the meat filling in the center in an all-length strip, keeping 2-3 cm uncoated all around.
Peel eggs and place them whole one in after the other in a line in the center of the stuffing strip. Depending on the length, you will need 3 or 4 whole eggs.
Cover the eggs with the remaining stuffing. Possibly keeping the bumps of the shapes of the eggs.
Wet the dough with water all around the stuffing.
Cover with the second puff pastry, which is therefore larger. Eventually, cut the excess dough but leave 2 cm of dough all around (see photos).
Press the two pastries to seal them and make small incision with a sharp knife throughout the thickness of the two pastries (again see photos).