Preheat oven to 350 F (176 C)
In a small bowl, whisk the flax seed and water until it forms a thick paste. Let sit while you prepare the rest of the ingredients.
Evenly spread the oats on a rimmed baking sheet and toast for approximately 5 minutes, or until they are lightly golden and have a wonderful nutty aroma. Put in a large mixing bowl.
In a large skillet, heat 3 tablespoon (45 ml) of the vegetable broth on medium heat and add the mushrooms and green onions. Cook for approximately 10 minutes, or until the mushrooms release their water and are browned. Add the garlic and cook for 2 minutes. Add 1 or 2 tablespoon (15 or 30 ml) of vegetable broth and scrape any stuck-on pieces in the pan and place in the mixing bowl with the oats. Add the spinach, basil, sun dried tomatoes, olives, rosemary, dried Italian seasoning, salt and pepper, and flax mixture and stir until well combined. Add the remaining broth to the bowl and stir until well combined.
Pour the oat mixture into a 9-inch (23 cm) round or square pan and bake for 30 to 35 minutes, or until the oats are firm and golden brown on top. Let sit for 5 minutes before cutting.