First, make the persillade: peel and mince the garlic and parsley. Using a fork, combine with the butter.
Mince the shallots and rinse the prawns with running water.
Heat a frying pan over medium heat and add a knob of parsley butter.
Once the butter has melted, sauté the shallots for a several minutes.
Then add the prawns and sauté for 5 minutes over high heat. Add a small knob of butter if necessary.
Then add the cognac and immediately flambé the prawns.
Before serving, salt and pepper, and add the thyme and chilli pepper.