Grease a soufflé dish well with butter and dust sides with parmesan. Preheat oven to 190ºC and place baking sheet in oven.
Melt butter in a pan, add the flour to make a roux, then add the milk gradually. Simmer until thickened, remove from heat. Allow to cool slightly. Beat in the egg yolks and cheese.
Season chopped prawn meat with salt, cayenne and nutmeg. Fold into the cheese mixture.
Then gently fold through egg whites.
Place soufflé mix into prepared dish and bake for 25-30 min or until puffed and golden. Toss the crushed peas with mint leaves and serve.