Preheat oven to 400 degrees Fahrenheit
In a 9 X 13 roasting pan combine your mushrooms, onion, garlic, thyme, chili flakes and green olives.
Pour 1/3 cup olive oil over the ingredients in the roasting pan and using a rubber spatula carefully mix everything together so that all ingredients are coated in oil and the herbs are well distributed. Place the fresh rosemary sprigs over the top.
Position your mushrooms so that you have an empty space in the center of your baking pan. Place your feta into this space and then sprinkle the top of the feta with the pepper and oregano.
Place your roasting pan in the bottom rack of your oven and bake until the mushrooms are caramelized. This will take about 25-30 minutes.
During the last 10 minutes of baking; boil your pasta according to the package directions. Reserve 1 cup of the pasta water, in case it's needed. Drain, and set aside.
When the mushrooms are ready; carefully remove the pan from the oven, and using a fork, mash the feta, and mix all the ingredients together.
Sprinkle with the salt, lemon zest, and juice from half a lemon
Add your drained pasta and carefully mix it all together. If your pasta is too dry, add a bit of the cooking water that you had reserved.
Serve immediately with a drizzle of olive oil, a splash of lemon juice, and top with some chopped up fresh parsley.
Enjoy!