For prawn topping (optional) - Dab the prawns dry using paper towels. Heat the olive oil in a large, deep frying pan over medium-high heat. Place in 8 prawns and fry for 1 to 2 minutes per each side or until cooked through. Transfer prawns onto a plate, then cover loosely with foil to keep warm.
If attached, remove the tail shell from the remaining prawns, then chop into little chunks.
Use paper towels and carefully wipe the same frying pan clean. Melt the butter over medium heat, then add the garlic and sauté for a minute. Stir in the orzo to cover it in butter, then pour in the stock. Add the salt and stir regularly during cooking so it doesn't catch on the bottom of the pan. Cook until most of the liquid absorbs into the pasta; this should take about 8 to 10 minutes.
Try the orzo, it should be al dente like regular pasta, tender but slightly firm. If the orzo isn't done and the liquid looks low, add a little more stock a little at a time until you get the right consistency. Alternatively, if the orzo is done and it's too wet, use a spoon to remove some liquid.
Stir in the chopped prawns, and cook until they change colour, then add the cream and Parmesan cheese. Continue to stir until the cheese has melted into the sauce. Cook for another 5 minutes or until the pasta has heated though. Add the lemon juice and parsley, stir to combine, then remove from heat.
Have a taste and adjust to your liking by adding more salt, pepper, or lemon juice if needed. Top orzo with prawns (if using) and serve with more Parmesan and parsley if desired. This pasta is best served immediately. Enjoy!