Place a large skillet over medium-high heat with two turns of the pan of EVOO, about 2 tablespoons. Add the mushrooms and garlic to the pan and cook, stirring occasionally, until deep golden brown, 6-8 minutes.
Add the sherry to the pan and cook until reduced, about 1 minute. Add the butter, parsley and some salt and pepper to the pan. Stir to melt the butter and combine.