Prepare white beans according to packet directions.
Preheat oven to 200oC fan forced. Place potato, sweet potato, beetroot, garlic and oil in a bowl. Toss well to combine. Place mixture on a tray in a single layer. Season with salt and pepper. Roast for 30 minutes.
Turn potato and sweet potato. Add capsicum, red onion and rosemary to the tray. Roast for 15 minutes and then add pine nuts to vegetables and roast for a further 5 minutes or until vegetables are browned and tender. Set aside for 10 minutes to cool slightly.
To make the dressing, combine the yoghurt and tahini. Season to taste.
Combine roasted vegetables, pinenuts and beans with the rocket. Pour over dressing and top with feta. Serve.