Place sugar, evaporated and condensed milk in a saucepan. Bring to a boil over medium heat, stirring constantly, until thick and the bottom of the pan can be seen. Remove from fire.
Lightly beat egg yolks and add to milk mixture. Return to low fire for 3 to 4 minutes. Mixture must not boil. Remove from fire, add vanilla and butter and stir until combined. Cool.
Whip egg whites until thick and fold into manjarblanco carefully. Fold in almonds and transfer to a serving bowl. Sprinkle cinnamon on top.