Step by step
In a large bowl combine the mayonnaise, garlic, mustard and parmesan and beat well.
Add the radish, most of the spring onion and shredded chicken breast to the bowl and stir well so everything is coated.
Separate the leaves of the Little Gem lettuce and lay out on a platter. Spoon a little of the chicken mix into each lettuce leaf and top with the extra parmesan and left over spring onion.