Preheat your oven to 400°F (200°C).
Scrub the beets thoroughly under cold water to remove any dirt.
Wrap each beet individually in aluminum foil and place them on a baking sheet.
Roast the beets in the oven for 45–60 minutes, depending on their size. You’ll know they’re ready when you can easily insert a fork or knife into them.
Once cooked, remove the beets from the oven and allow them to cool. When cool enough to handle, peel off the skin (it should come off easily).
While the beets are roasting, toast the walnuts. In a dry skillet over medium heat, toast the walnuts for 3–5 minutes, stirring occasionally. Once they become fragrant and lightly browned, remove them from the heat and set aside.
In a small bowl, whisk together the balsamic vinegar, olive oil, honey, salt, and pepper to make the dressing.
Once the beets are peeled, slice them into wedges or cubes, depending on your preference.
In a large salad bowl, add the mixed greens and top with the roasted beets, crumbled goat cheese, and toasted walnuts.
Drizzle the dressing over the salad and gently toss everything together.
Serve the beet salad immediately, or chill it in the refrigerator for a refreshing, cool dish.