Step 1

Bring a large pot of salted water to a boil.

Step 2

Heat the oil in a large skillet over medium heat until it moves easily across the pan. Add the onion, carrot, celery, salt and pepper, and cook, stirring occasionally, until the vegetables begin to soften, about 5 minutes. Add the garlic, cook for 1 minute, then add the mushrooms and thyme leaves. Cook, stirring frequently, until the mushrooms are almost tender, about 3 minutes. Add the tomato, cook about 2 minutes more, then add the stock, 2 tablespoons at a time, bringing the pan to a simmer before each addition. Simmer the Bolognese until it is concentrated but not yet dry, about 30 minutes. Set aside to cool.

Step 3

While the Bolognese is cooking, cook pasta in boiling water according to package instructions.

Step 4

When pasta and mushroom are both finished, toss together until combined and serve. Top with fresh Parmesan, if desired.