Bring a large pot of water to the boil. Add a big pinch of salt and the pasta. Cook for the time per the packet instruction.

Heat oil in a skillet over high heat. Add prawns and cook for 30 seconds, until surface just changes from translucent to opaque.
Add chili flakes and garlic.

Add tomato dices, pasta sauce, squeeze of lemon juice, parmesan, salt and pepper. Bring to simmer, turn heat down to medium and cook sauce for 1 minute, stirring frequently (don't cook for long otherwise will overcook prawns).

Add pasta, about 1/2 cup of pasta cooking water and parsley. Toss gently for 1 minute (or gently stir with wooden spoon or tongs) until sauce re-thickens and it coats the pasta.
Adjust salt, pepper and spiciness to taste.