Place ice in blender and pulse several times, to begin breaking it up. Add raspberries, club soda, lemonade mix, 1 tablespoon lemon juice, and tequila and blend until thick and smooth, about 30 seconds.
Pour 1 tablespoon or so of lemon juice into a small saucer. In another saucer, pour a thin layer of salt (table salt, or kosher is even better). Dip the rims of the glassed in the lemon juice, then the salt. Pour frozen mix into salted glass and serve.
Recipe courtesy of Ingrid Hoffmann