Chop the mushrooms finely and mince or chop the garlic too.
Heat a cast-iron skillet and add in some oil or butter.
Cook the mushrooms until they are well browned.
Turn down the heat to medium and add the garlic. Cooking and stirring for a minute or so just until they release their aroma. Do not colour them.
Remove the pan from the stove, put the fried mushrooms and garlic in a separate bowl and let it cool to room temperature.
Meanwhile, chop some parsley with a sharp knife.
When the Mushroom mix has cooled down, add it to the room temperature butter along with the chopped parsley and seasoning.
Once you have mixed it all together. Store it in the fridge wrapped up or do the following for easy portioning.
Lay a piece of parchment flat on the table. Place the butter on the parchment and place another piece of parchment on top. roll out to 5mm thick and close the parchment so that you have a thick envelope of garlic butter. Store in the fridge until needed.
Notes
Make sure the butter is room temperature and not fridge cold or melted.
Make sure the mushrooms have cooled down completely before adding to the butter.