Preheat the oven to 200°C (400°F).
Wrap the beetroots in aluminum foil and roast them in the preheated oven for about 40 minutes or until tender. Let them cool, then peel and slice them.
In a large bowl, combine the mixed greens, roasted beetroot slices, crumbled goat cheese, and toasted walnuts.
In a small bowl, whisk together the olive oil, balsamic vinegar, salt, and black pepper.
Drizzle the dressing over the salad and toss gently to combine.
Serve the salad immediately, enjoy!