Blend the pineapple up in a blender; it should blend on its own without any additional liquid, but feel free to add 1-2 tablespoon water to get it going.
Pour pineapple juice into a cocktail shaker, then add ginger beer, tequila, rosemary, and top it off with club soda until the shaker is close to full.
Shake, pour and enjoy!
Notes
*If using frozen pineapple, simply blend all ingredients except the rosemary in a blender until smooth.