Bring a pan of water to the boil and add the orzo. Cook for 5 minutes, then add the peas to the pan, stir and let it all cook for a further 5-6 minutes.
Heat a large non-stick frying pan over a medium-high heat, and add the olive oil and half the butter. Once melted, add the prawns and garlic, stirring occasionally. Once the prawns are pink, firm and piping hot all the way through, squeeze the juice of most of the lemon into the pan. Reserve the lemon for an extra squeeze of juice at the end.
Add the chopped parsley and the rest of the butter. Gather half a ladleful of the pasta cooking water and add to the prawn pan, giving it all a good stir. Season with black pepper.
Reserve some of the pasta cooking water in a mug, then drain the pasta and peas, and add to the prawn pan. Mix everything together and add an extra splash of pasta water if you need to loosen the sauce.
Serve with an extra squeeze of lemon juice and a little black pepper on top. Adults, you may want to season your portion with salt at the table.
