Trim all fat from lamb chops. Season with salt and freshly ground black pepper; brown on both sides in a hot pan with a little olive oil. Chops should remain very rare on the inside. Cool.
Roll out puff pastry into 8 circles big enough to encase chops. Spread duxelles of mushrooms on top of chops. Place 1 chop on each circle of dough and wrap in pastry, leaving bone out; moisten