Preheat the oven to 425 °F. Lightly spray a foil-lined baking sheet with nonstick spray.
In a large bowl, toss together the carrot pieces, the onion wedges, olive oil, coriander, cinnamon, salt and pepper.
Spread the carrots and onions in an even layer on the baking sheet and roast in the oven for about 30 to 35 minutes until carrots are deeply browned and fork-tender. Stir once at the 15-minute mark.
Meanwhile, bring 2 cups of chicken broth to a boil in a large stockpot.
When the vegetables are done roasting, remove them from the oven and transfer to the pot of boiling chicken stock.
Use an immersion blender to grind up the vegetables to a smooth consistency.
Swirl in 2 tablespoons of Greek yogurt for a little acidity, and top with some chives (or any fresh herbs you have)