Preheat the oven to 375°F (190°C). Wrap the sweet potato chunks in a large pocket of heavy-duty foil. Combine the all-purpose potatoes, garlic and 1⁄4 cup water in a roasting pan, tossing to coat. Cover the pan with foil. Place the roasting pan and the sweet potato pocket in the oven and bake until both types of potato are tender, about 45 minutes.
Transfer the all-purpose potatoes and the garlic to a large bowl. Add the sour cream and coarsely mash with a potato masher. Divide the potato mixture among 3 medium bowls.
Add the spinach, lemon rind and marjoram to one bowl of potatoes and coarsely mash together.
Drain the beets, reserving 1 tablespoon liquid. Add the beets, reserved liquid, orange rind and coriander to another bowl of potatoes and coarsely mash together.
Add the sweet potato, ginger and cayenne pepper to the third bowl and coarsely mash together. Serve the three-vegetable mash as a side.
preparation time 25 mins cooking time 45 mins
Per Serving: 211 calories, 7 g protein, 6 g total fat, 3 g saturated fat, 15 mg cholesterol, 33 g total carbohydrate, 9 g sugars, 6 g fibre, 190 mg sodium