Preheat oven to 425F, and line a baking sheet with parchment paper.
Peel and quarter the beets, and place on the baking sheet. Drizze with olive oil, cover with aluminum foil, and roast in the oven for 30-40 minutes.
While the beets are roasting, wash your baby greens and place in a serving bowl. Add in chopped walnuts, and if you are using it, feta or vegan cheese.
Once the beets have roasted and are cooled, add them to your baby greens and drizzle with the vinaigrette below just before serving.
For the Vinaigrette
Add all of the vinaigrette ingredients to a 500mL mason jar, cover with a lid and shake to combine.