Preheat the oven to 400°F (200°C).
Wash the beetroots thoroughly and wrap them in aluminum foil.
Roast the beetroots in the oven for about 45-60 minutes or until tender.
Remove the beetroots from the oven and let them cool.
Once cool, peel the beetroots using your hands or a vegetable peeler.
Dice the beetroots into bite-sized pieces.
In a large mixing bowl, combine the diced beetroots and shredded cabbage.
Add the chopped walnuts and crumbled feta cheese to the bowl.
In a separate small bowl, whisk together the olive oil and balsamic vinegar.
Pour the dressing over the salad and toss gently to combine.
Season with salt and pepper to taste and garnish with fresh herbs before serving.