Peel the onion and finely chop it. Peel and crush or finely chop the garlic. Separate the parsley leaves and stalks (save the leaves for later in the recipe), and finely chop the stalks.
Pour 1 tbsp oil into a pan and bring to a medium heat. Slide in the chopped onion, garlic and parsley stalks along with 1 tbsp curry powder and a pinch of salt and pepper. Sweat the veg for 3-4 mins, stirring occasionally.
Tip the pearl barley into the pan and crumble in the stock cube. Top up with 800ml boiling water and give everything a good stir. Bring back to the boil, then reduce to a simmer and cook for 18 mins, till the grains are tender.
Meanwhile, scrub, top and tail the carrots. Use the peeler to create ribbons, peeling down to the cores and then finely slice the cores. When the barley has cooked for 18 mins, swirl the carrots into the soup and continue to cook for a further 2-3 mins, till both the carrots and the barley are tender with a slight bite.
Taste the soup and add a little more salt and pepper if needed. Ladle into bowls and top with the reserved parsley leaves to serve.