Combine the flour and a good pinch of salt in a medium bowl. Rub the butter into the flour until it has the consistency of sand.

Add the water and briefly knead the dough by hand until it comes together. If the dough looks too dry, carefully add a little more water. Cover tightly with plastic wrap and let rest in the fridge for at least 30 minutes.

Season the chicken with the crumbled Maggi® chicken bouillon cube and some black pepper.

Heat a heavy-bottomed pot or Dutch oven over medium-high heat and add 1 tablespoon of margarine. Add the chicken and brown on both sides. Add a splash of water, cover the pot, and cook until the chicken is cooked through. Set the cooked chicken aside to cool slightly before shredding.

Wipe off the pot if necessary, then reheat over medium-high heat and add another tablespoon of margarine. Add the onions and garlic, cooking until softened. Stir in the tomato paste, taking care to mix well.

Add the peas and carrots, cocktail onions, cornichons, and capers. Season with the crumbled Maggi® chicken bouillon cube and some black pepper. Return the shredded chicken to the pot and mix everything well. Turn off the heat, and set the filling aside to cool.

On a lightly floured surface, roll out half of the pastry into a large rectangle (large enough to line the bottom and sides of the roasting tin) about 5mm (¼inch) thick. Ease the dough into the roasting tin, trim the edges, and prick the bottom with a fork.

Add the filling to the prepared tin and lay the sliced eggs over the top. Roll out the rest of the pastry and lay it over the top. Tuck the edges under themselves and crimp with a fork. Brush the top of the pastry with the egg wash, and cut a couple of slits in the top of the pastei for steam to escape.

Bake for about 45 minutes, or until the pastei is golden brown. Let cool for about 30 minutes. Serve with rice and sautéed vegetables (I like string beans) or by itself.