Preheat the oven to 350 degrees F (175 degrees C). Grease a loaf pan.
Mix eggs, spinach, mushrooms, bread crumbs, onion, milk, blue cheese, Worcestershire sauce, garlic, cayenne pepper, oregano, basil, salt, and black pepper together in a large bowl. Add ground beef and mix thoroughly with your hands; pack into the prepared loaf pan.
Bake in the preheated oven until no longer pink in the center, 45 to 60 minutes. An instant read thermometer inserted into the center should read at least 160 degrees F (70 degrees C).
Heavenly Meatloaf with Blue Cheese, Mushrooms, and Spinach · Dinner Match Lab | Dinner Match Lab