Preheat oven to 425 degrees F.
Spread carrots, onions, garlic and fresh ginger in a large pan or on a rimmed baking sheet. Sprinkle with salt and drizzle with olive oil. Roast for 20 minutes. Remove from pan, drizzle with maple syrup and roast for another 18 to 25 minutes. Toss vegetables with butter.
Add about half of the broth to the blender, then add roasted vegetables. If you are using ginger from a tube or anything other than fresh ginger, add it as well. Also, be sure to let the mixture cool a little before you puree it. If your vegetables are hot and your broth is room temperature, this should only take about 5 minutes.
Puree soup. Transfer to a large pot and heat.
To serve, spoon into bowl and serve as is, or add a spoonful of Greek yogurt to each bowl for a little protein.