Creating the Easy One-Pan Baked Tilapia and Vegetable Casserole is simple, and following these steps will guide you to a delicious outcome:

1. Preheat the Oven: Begin by preheating your oven to 400°F (200°C).
2. Prepare the Vegetables: In a large mixing bowl, combine broccoli, cherry tomatoes, bell pepper, onion, and garlic.
3. Season the Vegetables: Drizzle the olive oil over the vegetables. Sprinkle oregano, paprika, salt, and pepper. Toss to coat the vegetables evenly.
4. Arrange in Pan: Spread the seasoned vegetables evenly in a large baking dish or a sheet pan.
5. Add Tilapia: Place the tilapia fillets on top of the vegetables.
6. Season the Fish: Squeeze lemon juice over the tilapia and season with additional salt and pepper if desired.
7. Bake in the Oven: Place the baking dish in the preheated oven and bake for 25-30 minutes or until the fish is flaky and the vegetables are tender.
8. Garnish: Once done, remove from the oven and garnish with chopped parsley.
9. Serve: Allow to cool for a few minutes before serving.

Following these straightforward steps will yield a delectable casserole that is sure to impress.