For the asparagus, preheat a grill to 200°C and line a tray with foil. Arrange the spears flat alongside one another. Add a little salt and olive oil.
Cook asparagus for about 5 minutes, turning halfway through. They may need a little longer if they're thick spears, but don't overcook them as they're best when they're a little crunchy.
For the barley, rinse with water in a sieve, then add to the stock or water in a large saucepan. If you're using water, add 1 tsp salt. Bring to a boil, then turn down to a simmer and cook for approximately 25 minutes. By this time, it will have tripled in volume, and be soft, but a little chewy. Once cooked, drain any remaining liquid.
To serve, spread the barley onto a large plate, put the asparagus spears on the top, then drizzle with the sauce.