Rinse the rice under cold water until the water runs clear. In a large pot, bring the vegetable broth to a boil and add the rinsed rice. Reduce heat to low, cover, and simmer for 15-20 minutes, or until the rice is cooked and the liquid is absorbed. Remove from heat and let it sit covered for 5 minutes.

While the rice is cooking, heat the olive oil in a large skillet over medium heat. Add the diced onion and sauté for about 5 minutes until translucent. Stir in the minced garlic, salt, pepper, and paprika, and cook for an additional minute.

Add the chopped spinach and parsley to the skillet, cooking until wilted, about 2-3 minutes. Stir in the frozen peas and cooked rice, mixing well to combine all ingredients.

Preheat the oven to 400°F. In a baking dish, spread the rice mixture evenly and place the fish fillets on top. Season the fish with salt, pepper, and dill if using. Arrange lemon slices over the fish.

Cover the baking dish with foil and bake for 20-25 minutes, or until the fish is cooked through and flakes easily with a fork.

Remove from the oven and let it cool for a few minutes before serving. Garnish with additional fresh herbs if desired.