Meanwhile, make the eggs. In a medium-skillet over medium heat, add the ghee. Once melted, add in the white parts of the green onions, reserving the green parts for the cream cheese spread. Sauté for 2 minutes, until they just start to soften.
Add in the baby arugula or spinach and salt. Stir to combine and cook until wilted, about 2 minutes. Remove from the heat and set aside.
In a large mixing bowl, add the eggs, milk, salt, turmeric, and pepper. Whisk very well until pale yellow and fluffy.
Line a 9x13 pan with a parchment sling and grease generously with avocado oil cooking spray. Add in the cooked onions and spinach, arranging it evenly on the bottom of the pan. Pour over the eggs, and carefully transfer to the oven. Bake for 17-20 minutes until the eggs are totally set and have risen.
Remove from the oven and allow to completely cool before assembling your sandwiches. This is less critical if you make the sandwiches fresh, but if you plan to freeze them, all components must be at room temperature. Otherwise, the steam from the eggs will cause the sandwiches to get soggy and icy in the freezer.
Once the eggs have cooled, remove from the pan using the parchment sling. Cut the eggs into 8 even squares and set aside for assembly.