Preheat your oven to 375°F and lightly grease a small oven-safe baking dish with the ghee.
Place the bacon slices in a cold skillet and turn the heat to medium; cook until nearly crisp.
Brush the maple syrup onto the bacon slices and cook for 1 additional minute until caramelized, then remove and chop into small pieces.
In the same skillet, sauté the sliced mushrooms and baby spinach for 2-3 minutes until the mushrooms are tender and spinach is wilted.
In a mixing bowl, vigorously whisk the eggs, egg whites, Greek yogurt, sea salt, and black pepper until the mixture is smooth and aerated.
Fold the chopped maple bacon, sautéed mushrooms, and spinach into the egg mixture.
Pour the mixture into the prepared baking dish and bake for 20-25 minutes, or until the center is set and the top is lightly golden.