01 - Combine lemon juice, lemon zest, sugar, milk, vanilla extract, and ice cubes in a blender. Blend until completely smooth and frothy, approximately 30-45 seconds.
02 - In a clean, dry bowl, beat egg white with cream of tartar until soft peaks form. Gradually add sugar while beating continuously until glossy, stiff peaks form and the mixture holds its shape.
03 - Pour blended lemon mixture evenly into two tall glasses. Spoon or pipe the prepared meringue generously on top of each glass, creating a fluffy, peaked crown.
04 - Sprinkle with fresh lemon zest and crushed graham crackers. Serve immediately with straws and spoons. For a toasted marshmallow effect, lightly torch meringue with a kitchen torch until golden-brown.