In a skillet over medium heat, heat coconut oil. To the skillet, add onions and cook until translucent. To the onion mixture, add the mushrooms and broccoli, and cook for 3 to 5 minutes then stir in spinach, garlic, and salt and pepper. Slowly pour eggs evenly over vegetables.
Cook egg for 3 to 5 minutes, until egg is firm. Flip the frittata and cook for another minute or two, until cooked through.