Heat one tablespoon of the olive oil in a medium saucepan over medium heat. Add the onions and cook for 4-5 minutes or until softened. Add the garlic and cook for one minute or until fragrant but not brown.
Add the chicken broth and bring to a boil. Slowly stir in the polenta. Reduce heat to a very low simmer and cook, uncovered, stirring occasionally, for approximately 15 minutes or until the polenta has thickened. (I like there to be a little soupiness remaining, as the polenta will continue to thicken as it sits. You may season to taste; I found the salt in the broth to be sufficient at this point.)
Meanwhile, in a medium sauté pan, heat the other tablespoon of oil over medium heat. Add the mushrooms and sauté for 8-10 minutes, stirring occasionally, or until their liquid has been released and the mushrooms are golden brown. Season with salt and pepper. (Here, I used the 1/4 teaspoon of each.)
When the polenta is finished cooking, remove from the heat and stir in the Parmesan cheese. You may stir in the mushrooms or top the polenta with them.
Sprinkle with chopped fresh parsley and enjoy!