Preheat oven to 400°F. Gently rub the dirt off the mushrooms with a damp paper towel. Take off the stems and set aside. On a baking sheet with parchment paper, place the mushroom heads round side on top. Cook for 10 minutes.
Chop up stems into small pieces. In a skillet on medium heat, place chopped stems, onion, and garlic. Cook about 5 minutes until onion is softened and stems are cooked. Add the salt, thyme, and oregano. Keep on the heat for another minute, then take off the heat and pour into a large bowl.
Add the almond flour and fresh chopped parsley to the mushroom mixture. Mix it until it looks like it's all starting to stick together.
Flip mushroom heads over, so the bottom is facing up and scoop the filling into the mushrooms. Really pack each mushroom. Try and use all of your filling. Bake for another 10-15 minutes until the filling starts to brown a little on top. Enjoy hot.