Scrape and clean the mussels, removing the beards and discarding any broken or open ones, and wash them under running water several times. Put the mussels in a deep, wide pan with 1 dl water, salt, pepper, and the bouquet garni. Cover and cook over brisk heat until all the mussels have opened.
Remove the mussels and shell them, reserving the flesh. Melt 30 g of butter in a frying pan and sauté the mussels in it for 2-3 minutes, then flambe' with the brandy and keep warm (but take care not to cook them further).
Break the eggs into a bowl with the cream, salt and pepper to taste, and whisk them lightly with a fork.
Melt the remaining butter in a pan, pour in the eggs and stir with a wooden spoon over gentle heat until the eggs are set but still soft. Fold in the mussels and the chopped herbs, and serve piping hot.