You will need to stir more often towards the end of the cooking time to prevent the rice sticking. Add a splash of water if needed. Stir in the peas and half the cheese and cook for 3 minutes more ...
It may be too prosaic to describe this as a frittata made with boiled rice — it is much better than that. All it needs is a simple green vegetable like green beans or sweet-stem broccoli to go ...