Clean the mushrooms by removing the stem and scraping out the gills using a spoon. This is optional but I recommend it. I save the stems to cook separately or chop up to use in a different recipe.
Brush the mushrooms with steak sauce (and oil if using), I used about ¼ cup for each. Allow to marinate overnight or at least an hour for the best flavor.
If baking:
Put into a baking dish, and bake at 350 F/ 175 C for about 15 minutes.
Flip over and bake another 15 minutes.
If grilling:
Add to a hot grill pan and cook for 3-5 minutes on each side, until nice and browned.
If using an outside grill, cook for 3-5 minutes over a medium flame and flip over, making sure to watch for burning.
Serve with sides of your choice!
Notes
If making the homemade steak sauce, make the entire recipe and use any extra to drizzle on top. Make double the sauce if you want a lot left to drizzle on top.
These pair with just about anything, see the post for more ideas.