Cream together the butter and one-half cup of the sugar until very light. Beat in the egg yolk.
Sift the flour gradually over the batter, mixing until all flour is incorporated. Using a wet knife or spatula, spread the dough on a greased and lightly floured cookie sheet (14 by 18 inches). Spread batter as thinly as possible.
Beat the egg white until stiff and spread it over the dough. Combine the almonds, cinnamon and remaining sugar and sprinkle the mixture over the meringue-topped dough.
Bake for ten to fifteen minutes, or until golden brown. Immediately cut the cake into one-and-one-half-inch diamond shapes. Cool.