Preheat your oven to 350 degrees f.
In a glass mixing bowl, whisk eggs, milk, dry mustard, oregano, a pinch of sea salt and pepper. Set aside.
Heat ghee/oil in a large skillet over medium-high heat.
Add in leeks and mushrooms and saute for about 4 minutes, until soft. Season with a pinch of sea salt and pepper.
Divide the sauteed mushroom leek mixture equally among the cups of a 6 large muffin tray.
Pour the egg mixture equally over the top of your mushrooms, then bake for 15-17 minutes, or until the eggs are just set and puffed. Ovens vary, so keep a close eye the first time you make these.
Enjoy warm, with a side of fresh berries, OR:
Refrigerate for up to 4-5 days in a sealed container for Meal Prep.