Preheat oven to 425.

Heat 2 large skillets over high heat.  Working in 2 batches divide the olive oil between the 2 pans.  When the oil is hot but not quite smoking, add the mushrooms and let saute for a few minutes, season with salt and pepper, add the butter to each pan and allow to carmelize.  Once mushrooms have cooked down to half their volume, transfer all mushrooms to 1 pan.  Add the shallots and garlic and cook until they are light brown and fragrant.  Add the thyme until it crackles then add the cream and bring up to a simmer.  Reduce the cream by half and stir in the grated parmesan, and the lemon juice.  Shut off the flame and quickly stir in the beaten egg.  Remove from the stove and let cool to room temperature.  Add the parsley and stir. While the mushroom mixture is cooling, roll out the pastry dough on a floured surface enough to line a 10 or 12 inch removable tart pan (I have used regular tart pans as well).  Put dough in tart pan and trim any edges.  Use fork to prick the dough and then cover with parchment paper and place the beans or weights on top of parchment in tart shell.  Bake for 10 to 12 minutes, remove from the oven and let cool to room temperature.  Remove beans and paper.

Lower oven to 400 degrees.

When both the filling and the shell have cooled to room temperature fill the shell with the mushroom mixture and top with the crumbled blue cheese.  Arrange the tart mold on a cookie sheet and bake for 20 to 30 minutes.  Remove from the oven and allow to stand for 15 minutes if you want it warm or let cool to room temperature before slicing