Preheat the oven to 450 degrees and set rack on lower third. Butter a 2 litre gratin or other baking dish.
Scatter the raspberries evenly in the dish and sprinkle with the sugar and the eau de vie.
For the batter, whip the whites with salt until they hold a very soft peak. Beat in the sugar very slowly until the whites hold a firm peak. Whisk the yolks until liquid and fold into the whites with the flour.
Spoon the batter over the raspberries in 8 to 10 separate mounds. Bake about 10 minutes, until well risen and golden brown. Sprinkle with confectioners sugar and serve immediately.