Preheat the oven to 350º F (175ºC). Brush bottom and sides of pan with oil. In large bowl, combine hash brown potatoes and melted butter, seasoning with salt and pepper to taste. Spread hash browns on bottom of pan. Bake 12 minutes. Steam the broccoli florets for 2 minutes in microwave. Heat olive oil in large skillet over medium heat. Sauté onion until softened, about 5 minutes. Add mushrooms, sautéing until they release their juices and liquid evaporates, about 10 minutes. Add bell pepper, broccoli and garlic and sauté until garlic is fragrant and peppers are beginning to soften, about 2 minutes. Season to taste with salt and pepper, and remove from heat. Beat eggs, milk, Tabasco, salt and pepper together with an electric mixer until thoroughly combined. Evenly spread the vegetables over the hash browns. Sprinkle with cheese. Pour egg mixture evenly over the top. Bake 30-35 minutes or until set in the middle. Serve with salsa, if desired.