Bring a large pan of salted water to the boil, and cook the pasta until tender with a bite at the centre, about 10 minutes. Drain.
Meanwhile, clean and peel the prawns, leaving their tails on. Crush the garlic.
Add garlic, prawns, lemon juice, parsley and chilli flakes into a bowl and mix together.
Heat a large, non-stick pan until hot. Add the prawn mixture, chicken stock and fromage frais to the pan and cook for 3 to 4 minutes until the prawns turn pink and are cooked through.
Season to taste with salt and pepper.
Add the boiled pasta and stir while warming. Serve immediately.