Prep oyster mushrooms: if mushrooms are dirty, take a damp paper towel and gently wipe away any excess dirt. If there is dirt on the stems, you can scrape that off with a knife or cut those parts away. Tear mushrooms into smaller, individual pieces
Heat olive oil on a large pan over medium heat. Cook shallots and garlic for about 2 minutes, stirring frequently, until lightly browned and fragrant.
Add mushrooms to the pan, stir continuously for 1-2 minutes, until covered in oil.
Then, allow mushrooms to cook undisturbed for about 3 minutes. Toss and cook undisturbed for another 3 minutes. The mushrooms should start to shrink and brown.
Stir in red wine vinegar, lemon juice, and parsley. Season with salt and pepper, as desired. Continue to cook for another 3 minutes, stirring occasionally.