Lay the tomato slices on a baking sheet lined with parchment paper and sprinkle them with a pinch of salt and pepper and a drizzle (1 tablespoon) of good olive oil. Roast them in the oven for about 20 minutes. Then remove them and set aside.
In an oven-proof skillet, heat the remaining 3 Tbs olive oil and sauté the anchovies for a few seconds until they become fragrant. Season the oil with the tomato paste, salt, pepper, dried Italian herbs, and garlic powder. Allow this seasoning mixture to cook for about 60 seconds.
Mix the seasoned oil with the cooked rice. Toss in the peas and stir to combine. Toss in the shrimp and the roasted tomatoes and bake the whole dish in the oven for 20-25 minutes or until the shrimp are cooked through and the rice is warm. Remove and garnish with chopped fresh herbs and serve immediately.