Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking dish.

In a skillet over medium heat, add olive oil and sauté diced onion and minced garlic for 3-4 minutes until translucent.

Add sliced mushrooms and chopped broccoli to the skillet, cooking for an additional 4-5 minutes until tender.

In a large bowl, whisk together the eggs, milk, salt, and black pepper.

Stir the cubed stale bread into the egg mixture to soak evenly.

Add the sautéed vegetables and shredded cheese to the egg and bread mixture, folding gently.

Pour the mixture into the greased baking dish and spread evenly.

Bake for 35-45 minutes until the eggs are set and the top is golden brown.

Remove from the oven, let cool for 5-10 minutes, then slice and garnish with parsley or chives.