Using a citrus press, squeeze the lemon juice into a jar. This can be done ahead of time and refrigerated.

Prep the glasses by running a lemon slice around the rims. Pour some sugar and grated lemon zest onto a plate and press the rims of glasses onto the plate to get a nice sugared rim.

In a large blender, combine the lemon juice, frozen strawberries, vodka, and simple syrup. Blend until smooth. Add ice until the desired consistency is reached.

Pour the slushy mixture into the prepared glasses. Garnish with lemon slices and enjoy!