Preheat the oven to 180ºC.
In a large bowl, whip the egg whites with a pinch of salt and add the sugar little by little once the whites have started to foam, till you have a stiff meringue.
When the meringue is stiff, add the flour by the spoonful while slowly beating.
Whip the cream to soft peaks. Add it to the meringue-flour mixture and mix carefully and gently with a spatula.
Line a rectangular cake dish with parchment paper (typical bicas are rectangular and wrapped in paper).
Butter the paper and pour the batter (we used a round springform 22 cm diameter).
Smooth the surface with a spatula, then sprinkle sugar and cinnamon on top for a perfectly genuine finish (we just mixed the cinnamon with the batter).
Bake 35 minutes or until done.