Preheat your oven to 425°F. Trim the tops and roots off the beets. Wash thoroughly, scrubbing with a vegetable brush. Then, cut in half for roasting.
Place the beets on the baking sheet and drizzle with oil. Season with salt and pepper and toss to coat. Roast the beets for 45 minutes.
The pieces should be tender when poked with a fork. If needed roast another 5-10 minutes. Use a paring knife to remove the skins and thinly slice the beets.
To Make the Salad
Spread the greens across a large platter, place them in a salad bowl, or divide them between individual plates or bowls.
Layer the sliced beets over the greens. Top with goat cheese and walnuts. Lightly drizzle with balsamic vinaigrette before serving. Toss each salad, if desired, before serving.