Preheat the oven to 200°C (400°F).
In a roasting tin, toss the oil, onion, broccoli, garlic, paprika, salt, and pepper until coated.
Bake for 10 minutes to soften the vegetables.
Remove from the oven, then stir in the orzo, pesto, and vegetable stock. Mix well.
Cover the dish tightly with a lid or foil and bake for another 15 minutes.
Remove the cover, stir in the peas, and sprinkle the grated cheese over the top.
Bake uncovered for a final 5 minutes, or until the cheese is melted and bubbly.
Check that the orzo is tender and serve hot.