In a small cast iron skillet over medium heat, melt the butter. Add the mushrooms in and saute for 7-8 minutes or until they have shrunken and turned golden brown.Add in the spinach until wilted and has released its liquid. *Set aside to cool before adding to the egg mixture.
Make the Egg bites
Preheat the oven to 350℉. Line a muffin tin with baking cups and spray the cups with avocado oil spray. Set aside.
In a large mixing bowl add the eggs and heavy cream. Whisk vigorously to combine. Next, add the cooled spinach and mushrooms, grated cheese, salt and pepper. Stir it all together with a wooden spoon until everything is fully incorporated.
Use a ¼ measuring cup to fill each muffin well until it almost reaches the top of the liners. Sprinkle the top of each egg bite with a pinch of dried parsley.
Bake in the preheated oven for 12-15 minutes or until puffy and golden. Remove to cooling rack. Cool completely before storing in the fridge for up to 4 days.