I like to serve this large Pithiviers whole at the table, then
carve it up for guests. Very theatrical.
700 gmpuff pastryFor dusting:plain flour2egg yolks, beaten, for eggwashHerb crepes60 gmplain flour, sifted1egg200 mlmilk2 tsp eachfinely chopped chives and parsley1 tbspmelted butter Chicken mousse1 (375 gm)chicken breast, skin and sinew removed, well chilled60 gmeggwhite (about 2), chilled150 mlpouring cream, chilledTo taste:cayenne pepperMushroom duxelles1½ tbspolive oil3large golden shallots, thinly sliced2garlic cloves, coarsely chopped1sprig thyme1bay leaf200 gmbutton mushrooms, sliced3 (200 gm)king brown mushrooms, sliced150 gmoyster mushroom, coarsely torn20 gm (½ cup)dried porcini or morels or combination of both, soaked in ½ cup hot water for 1 hour¼ cupfinely chopped fine herbs, such as chives, tarragon, parsley and chervil
For herb crêpes, place flour in a bowl. Whisk egg and milk together, then gradually whisk mixture into the flour, season to taste, add the herbs and set aside to rest (30 minutes). Heat a 24cm non-stick frying pan on medium-high heat. Brush with melted butter and pour in enough batter to cover the base (about ¼ cup), swirl and tip out excess, then cook until batter is set (1 minute). Turn upside down on a clean surface and repeat with remaining batter - you'll need 5 crêpes. Cool, then cover with plastic wrap and set aside.
For chicken mousse, dice chicken and process in a cold food processor with a pinch of salt until smooth, then add eggwhite and continue processing until glossy (10-20 seconds). Transfer the purée to a cold bowl. Whisk in the cream and season to taste with salt, pepper and cayenne, and refrigerate until required.
For duxelles, combine oil, shallots and garlic with thyme and bay leaf in a large frying pan over medium heat and stir until softened but not coloured (3-5 minutes). Increase heat to high, add fresh mushrooms, season with salt and pepper and fry until golden and moisture has evaporated (5-6 minutes), then drain in a colander. Squeeze water from soaked mushrooms, coarsely chop and sauté briefly in the same pan to dry out (30 seconds to 1 minute), then add to fresh mushrooms. Remove the thyme and bay leaf (discard) and coarsely chop mushroom mixture, then spread on a tray and set aside to cool completely (20 minutes). Stir the fine herbs into the mushroom mixture, then mix into chicken mousse, adjust seasoning and refrigerate until required.
Preheat oven to 190C. Divide puff pastry into 300gm and 400gm portions and roll each piece on a floured surface to a thickness of around 5mm. Cut the 300gm portion into a 26cm round for the base and the other portion into a 30cm round for the top. Make sure you work quickly and the pastry stays cold. Place the smaller round on a cold, heavy oven tray lightly brushed with cold water (this prevents the pastry from warping in the oven). Overlap 3 or 4 crêpes on top to form a base and place the cold chicken and mushroom mixture on top. Fold the crêpes up and around the mousse to encase it, then place a crêpe on top. Brush around the pastry edges with egg yolk, then place the other pastry round on top. Press the edges together well, then, using a small pointy knife, cut around the base, leaving a good border of about 3cm. Brush the surface of the Pithiviers with egg yolk and refrigerate to set (10-12 minutes). Brush with yolk and refrigerate again, then score the top with a small sharp knife in a curved pinwheel pattern. Bake until shiny and dark golden brown and puffed (40-45 minutes). Rest for 15 minutes before serving.