Heat the oil in a pan and add the wild boar with a little bit of water. Simmer until it becomes partially tender. Add the tomato paste, stir. Season with salt and pepper. Add the mushrooms and continue to simmer. Add the Worcestershire sauce, a sprig of lemon thyme, the parsley and the chives. When the meat is almost done, sprinkle it with flour and lemon zest. Add a little water and cook further until it thickens.  
Preheat the oven to 180 degrees Celsius. Divide the pastry into two pieces and thinly roll it out. Place one piece into a round cake pan and spoon the stew on top of it. Cover with the other piece of pastry and fold the edges together. Optionally, add some decorations from the remaining puff dough, as pictured. Prick the top with a fork and brush with egg yolk. Place in the oven and cook for 45 minutes.