Wet the rim of your cocktail glass with water or a cut lime, and dip the rim into the black lava salt. Set the glass aside.
Add the lime juice, simple syrup, pineapple juice and Sour Apple pucker to a cocktail shaker.
Fill the shaker with ice, seal it up and shake well for about 15-20 hard shakes.
Fill your serving glass with fresh ice (I used nugget ice).
Strain the drink into the glass.
Measure out your butterfly pea tequila and carefully pour it onto the top of the drink. It should float easily, but if you are struggling, use the back of a bar spoon to help guide the liquid.
Serve and enjoy!
Notes
If you don't have Sour Apple Pucker liqueur, you can use Midori melon liqueur instead for a green colored drink. If you do, you will probably need to increase the amount of lime juice, since Midori is sweeter and doesn't have the sour flavor of the Pucker.
When you stir the liquid together, it will end up a reddish pink color.