Preheat your oven to 400°F (200°C).

In a large oven-safe skillet, heat the olive oil over medium heat. Add the diced onion and sauté for about 5 minutes until softened.

Stir in the minced garlic and cook for an additional minute until fragrant.

Add the rice to the skillet and stir to coat it in the oil and onion mixture. Cook for 2 minutes, stirring frequently.

Pour in the vegetable broth, and add the chopped parsley, spinach, oregano, salt, and black pepper. Bring to a boil.

Once boiling, reduce the heat to low, cover the skillet, and let it simmer for 15 minutes.

While the rice is cooking, season the fish fillets with paprika, salt, and pepper.

After 15 minutes, remove the lid from the skillet and place the seasoned fish fillets on top of the rice. Top with lemon slices.

Transfer the skillet to the preheated oven and bake for 15-20 minutes, or until the fish is cooked through and flakes easily with a fork.

Remove from the oven and let it sit for 5 minutes before serving. Fluff the rice with a fork and serve warm.