Cut the mushrooms into small cubes and then mince them with a knife into smaller pieces.
In a large skillet, saute the onion in olive oil over medium heat for about 5 minutes.
Add the garlic and mushrooms and cook them for about 10-15 minutes, until all the liquid has evaporated and the mushrooms have started to brown. (This is a great time to bring a large pot of water to a boil.)
At this point, add the tomato sauce, oregano, salt, pepper, and red pepper flakes to the mushrooms. Stir, and cook for 10 minutes. (While the sauce is cooking, throw the pasta into the boiling water and cook it for about 10 minutes, or until al dente.)
Scoop some water out of the boiling pasta and use it to thin the bolognese sauce and bring it to a nice consistency (you'll need about ½ cup). Add the drained cooked pasta to the mushroom bolognese. Stir everything well, garnish with fresh parsley, and serve.
How to Store it
This Mushroom Bolognese Pasta sauce is easy to store and also gets better with time. As the sauce sits, the spices and other ingredients marry together, giving the sauce an even richer flavor the next day. You can keep it fresh in the fridge for up to 4 days in an airtight container or covered dish. If you want to freeze it, just place the sauce in a ziplock freezer bag or tight-lidded container (leaving a little room at the top for expansion), and it can stay fresh for up to 3 months.
Can you Make this Sauce Ahead of Time?
Yes, this Mushroom Bolognese sauce is perfect for making ahead, and tastes great the day after. Just follow the recipe, but do not prepare the pasta (this is better fresh because it gets mushy as it absorbs sauce in the fridge). Allow the sauce to cool before storing it in an airtight container.When you are ready to serve it, cook the pasta while you reheat the sauce. Place the sauce back in the saucepan and warm it over low heat, stirring occasionally until it is steaming. Then toss the freshly made pasta in it and serve with a garnish of fresh parsley.