1. Preheat oven to 425 degrees Fahrenheit.Layer two cookie sheets with a sheet of aluminum foil.Peel and slice your carrots. Toss into a large ziploc bag.
2. Pour in 3 tablespoons of olive oil, cinnamon, chili powder, and shallot pepper. Seal the ziploc bag and massage to cover all carrots well in oil and spices.
3. Spread the carrots evenly on the cookie sheets.Roast for 45 minutes, until tender but not burnt. Set aside.In a large stockpot, heat the olive oil.
4. Add the onions and celery and saute for 5 minutes, until soft and shiny.
5. Pour in the carrots and top off with the chicken stock. Simmer for 15 minutes.
6. Cut the lemon in half and squeeze the juice into the pot. If you'd like it to be extra lemony, grate some of the zest into the pot as well.Puree the soup with a hand blender. If the soup comes out too chunky, add a little water to make it smoother.
7. Serve hot or chilled, with a dollop of yogurt on top.