Heat the oven to 350 F.
Sift the flour, measure it, add salt and baking powder.
Beat the egg whites until they are firm, with half of the sugar. Beat the egg yolks with the other half of the sugar. Add the cold water and beat until the sugar crystals are no longer felt under the spoon.
Folding the dough, gently incorporate the egg yolks into the beaten egg whites. Add the flour, salt, and baking powder.
Pour into a non-greased mold on the edges, but whose bottom has been covered with parchment paper.
Cook at 350 F, 20 to 25 minutes.
Unmold on a clean and damp cloth, then roll. After a few minutes, unroll and cover the inner surface with jelly or jam. Roll again, sprinkle with powdered sugar and let cool.