1/4 cup olive oil
1 cup diced sweet yellow onion (1/4-inch dice)
3 pounds butternut squash (peeled, seeded, and cut into 1-inch cubes, about 6 cups)
2 parsnips (peeled and cut into 1/4-inch slices, about 2 cups)
3 tablespoons grated fresh ginger
4 cups vegetable or chicken stock
2 1/2 cups carrot juice
1/2 cup apple juice
  salt (to taste)
  ground white pepper (to taste)
  A few gratings of fresh nutmeg
6 tablespoons mascarpone or crème fraîche (as garnish, optional)