Preheat the oven to 400°F (200°C).
In a large oven-safe skillet, combine the rice, vegetable broth, chopped spinach, parsley, dill, lemon juice, garlic powder, onion powder, salt, and black pepper. Stir well to combine.
Place the skillet over medium heat and bring the mixture to a gentle simmer. Once simmering, reduce the heat to low and cover the skillet. Cook for about 10 minutes until the rice has absorbed most of the liquid.
While the rice is cooking, prepare the fish. Pat the fish fillets dry with paper towels and season both sides with salt and pepper.
After 10 minutes, remove the lid from the skillet and carefully place the seasoned fish fillets on top of the rice mixture. Drizzle the olive oil over the fish and arrange the lemon slices on top.
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 a few minutes before serving. Fluff the rice with a fork and serve the fish on top.