Wash Scorpion potatoes, chop into 1 cm cubes. Place cubed potatoes into hot (not boiling) water, then bring water to the boil. Cook until al dente. Potatoes should be firm but cooked through. Drain and cool.
Cut Scorpion red onion and red capsicum in 1 cm pieces, lightly brush onion, capsicum and potatoes with olive oil.
Use hard (woody) rosemary stalks and strip most leaves, leaving the tips, and soak in cold water for at least 10 minutes prior to assembling.
Grill the potatoes, capsicum and onion on a barbeque hotplate, 1 minute each side or until lightly charred.
When cool enough to handle, assemble by alternatively threading the cooked potato, onion and capsicum onto the soaked skewers.
Drizzle lightly with olive oil, season with salt flakes and serve immediately.
Depending on your cooking method and technique the level of GI may vary.