To kill the yabbies, place them in a deep bowl and wrap the bowl tightly in a towel. Place the bowl in the freezer for 1 hour. Bring a large pot of salted water to the boil. Add the yabbies and cook for 5 minutes, or until the yabbies turn orange-red and the tails are tightly curled. Drain the yabbies and refresh in a sink of cold water to stop the cooking process.
To remove the yabbie meat, twist off the head where it meets the body. Use strong kitchen scissors to cut through the centre of the underside of the tail and gently peel the shell away from the meat. Remove the dark intestine if it is present (this generally applies to wild yabbies, but not to farmed ones).
To make the salad dressing, combine the olive oil, lemon juice, Dijon mustard, caster sugar, garlic and salt and pepper to taste in a screwtop jar. Shake well to combine.
Place the salad leaves in a large serving bowl. Add the avocado and yabbie meat. Pour on the salad dressing and toss gently to combine. Season to taste with salt and pepper and serve immediately.
Balmain Bug Salad: Replace the yabbies with 12–16 fresh Balmain bugs (also known as Moreton Bay bugs). Kill, cook and prepare the Balmain bugs in the same way as the yabbies.