Heat a large skillet over medium-high heat. Add the butter and bacon and cook, stirring frequently, until the bacon is rendered and crispy. Add the mushrooms and cook, stirring, until softened somewhat, 2 to 3 minutes, then add the onion and garlic and cook until the onion is very soft and the mushrooms are golden, about 4 minutes longer. Sprinkle the flour over the mushroom-onion mixture and cook, stirring, for 2 minutes. Whisk in the stock and cook until thickened, then add the cream, thyme sprigs, and season lightly with salt and pepper. Cook until the sauce has thickened enough to coat the back of a spoon and is flavorful, 12 ro 15 minutes. Stir in the turkey and adjust the seasoning if necessary.

Add the pasta and toss to coat well -- cook until just warmed through.

Sprinkle with the Parmesan and green onions and serve, garnished with more black pepper if desired.