Heat the oil in a saute pan over medium heat. Add the lardons. When they have some colour, add the shallots and garlic. Add the butter, thyme and mushrooms and turn up the heat. Stir from time to time. You want the mushrooms to be well coloured and rich and meaty. Remove from the heat (important) then add the drained pasta. Add a little pasta water.
In a separate bowl, mix the eggs with parmesan and marscapone. Season well with salt and pepper. Add to the pasta. Toss well, adding a little more pasta water if necessary.