Combine the flour, sugar, and cinnamon in a mixing bowl.
Cut the butter from the stick into small pieces, dropping them into the flour mixture.
Work the mixture with your fingertips until small crumbs are formed.
Add the egg yolk and work it in until the yolk is well distributed, then knead into a ball.
Press the dough into a 10 x 12-inch metal baking pan, using your hands.
Brush the top with the egg white; then sprinkle with the sugar-and-almond mixture.
Bake in a 350° oven for 15 to 20 minutes, or until lightly browned.
Remove from the oven.
Let cool a few minutes, then cut into 2 x 1-inch rectangles.
Finish cooling on a rack before removing the cookies from the pan.