Scrub and trim the beetroot without cutting through the skin. Place the beetroot in a roasting pan with a drizzle of olive oil, 1/3 of a cup of water and a sprinkle of sea salt and black pepper. Cover the pan tightly with foil and bake the beetroot in the oven at 180C for approx 50 minutes or until tender.
Once the beetroot is cool enough to handle, peel of the skin and cut the bulbs into easy to eat pieces.
Place the spinach leaves in a bowl then combine the olive oil, vinegar, mustard and seasoning together and toss most of the dressing through the greens, reserving a little to use at the end.
Arrange the spinach on small entrée plates and place the beetroot onto the greens. Sprinkle the walnuts and cranberries over the top and finish by crumbling the goat's cheese over the whole dish. Drizzle the remaining dressing onto each plate. Season with black pepper and serve.