Heat the olive oil in a pan over a medium heat. Add the onions and then sauté for 3-4 minutes, until softened.
Add the beetroot, stock, fresh parsley and borlotti beans and bring to the boil. Reduce the heat to simmer gently for 10 minutes, or until the beetroot has softened and iscooked through. Season, to taste, with salt and freshly ground black pepper, then blend with a hand blender until smooth.
To serve, pour into a bowl and garnish with a tablespoon of Greek yoghurt.