Preheat the oven to 400.
If not already done, peel and chop the beets and turnips. Spread on a baking sheet and toss with a about a tablespoon of the olive oil and a generous pinch of salt. Roast until tender to the bite, about 30-40 minutes.
Place the quinoa in a pot of the water or broth and bring up to a simmer. Cover and cook for 15-20 minutes until cooked through and tender to the bite.
In a medium bowl, whisk together the dijon, maple syrup, and apple cider vinegar. Continue to whisk rapidly and slowly drizzle in the olive oil. Season with a pinch of salt and the pepper.
Wash and dry the lettuce leaves well.
When the quinoa and veggies are cooked through, toss into the dressing and fold in the walnuts. Taste. Add more salt, pepper or even olive oil, if desired.
Serve a big bowl of the filling with the lettuce leaves and have guests fill their leaves as they desire. If you are a cheese fan, a crumble of blue or feta or similar would accompany this dish well, too.