Preheat the oven to 400°F (200°C).
Heat the olive oil in a large pan. Fry the bacon and mushrooms over medium-high heat until golden brown. Add the spinach towards the end and cook until wilted. Season with salt and pepper to taste.
Transfer the cooked bacon and veg to a greased baking dish.
In a bowl whisk the eggs, combine with the milk and onion powder. Season with salt and pepper.
Pour eggs over the bacon and mushrooms. Bake in the oven for 35-45 minutes or until set in the middle. Cover the casserole with tin foil if the top gets too brown, to prevent burning.
• Gluten free
• Paleo friendly
• Low carb
• Dairy free