Spray a large saucepan with low calorie cooking spray and place on a medium heat.
Add the onions and garlic and fry for 10 minutes, stirring, until golden and softened slightly.
Add the carrots, stock pot dissolved in boiling water and thyme, cover and simmer over a low heat for 25 minutes until the carrots and onions are tender.
Carefully transfer to a food processor and blitz until smooth. You may need to do this in two batches. Alternatively, use a handheld stick blender.
Transfer the soup back to the saucepan. Stir in the orange juice and season to taste with salt and pepper.
If needed, heat, uncovered over a low heat for 2 -3 minutes until piping hot and serve.