For the filling, simmer the spleens in the veal stock at low temperature for 20 min, remove, cool and pluck out the individual pieces from between the skins.
Mash the truffle with a fork, sauté briefly in butter together with the spleens, extinguish with Madeira, fill with heavy cream and cook until the spleens are coated with the cream sauce. Season with salt and pepper.
Pierce the veal fillet lengthwise in the middle with an abrasive steel or possibly a long kitchen knife and fill in the milt (using a wooden spoon handle). Season the fillet with salt and pepper, fry in clarified butter at moderate temperature until light brown all over and cool.
Spread the spinach leaves on a kitchen towel without gaps so that the fillet can be wrapped in them. Cover the spinach with plastic wrap and gently flatten with a pastry roller, then remove the plastic wrap repeatedly.
For the second filling, combine the salt, veal, cognac, cream and pepper (all well chilled) in the cutter until homogeneous, transfer to a pre-chilled baking dish and gently fold in the chervil, vegetable brunoise and snow. Coat the fillet all over, place it on the spinach, roll it up with a cloth and leave it to cool for 30 minutes.
Mix the egg yolks, oil and a pinch of salt to coat. Roll out the dough 2 mm thin, wrap the fillet in it, brush the edges of the dough with the egg yolk mixture and press it smooth. a