Place pearl barley into the Thermomix basket, rinse with water. Pour 1 litre of water into the Thermomix bowl and insert basket. Season chicken with salt and pepper and place into a lined Varoma dish and tray. Set into position. Cook 30 min/Varoma/speed 4. Slice chicken and set aside. Tip drained barley into a bowl. Set aside.
Drain the Thermomix bowl. To make the Balsamic Vinaigrette place garlic into the Thermomix bowl. Chop 3 sec/speed 6. Add remaining ingredients and blend 20 sec/speed 6. Pour over barley and stir to combine.
While the barley and chicken are cooking, assemble the salad on a large serving platter, starting with the salad leaves and building up until you have the cooked barley and chicken to add.
This keeps well for one day if you don't dress the salad greens; leave them seperate if you plan on eating it over a couple of days.