Preheat oven to 425°F.
Line baking sheet with aluminum foil or parchment. Toss carrots, onions, butternut squash, potato in canola oil, nutmeg, thyme, and salt and pepper then place on baking sheet.
Roast vegetables in oven for 45 minutes until browned.
Place roasted vegetables in a large pot and pour chicken stock, and bay leaf in and bring to a boil.
Once liquid boils and vegetables are soft remove bay leaf and blend with wand, or put in blender, or food processor in batches.
Blend until smooth. If too thick add more stock.
Serve hot with one tbsp of Plain Greek yogurt on top.