Remove the stems from the spinach; wash the leaves thoroughly, and pat dry. Cut into thin strips. Set aside.
Saute onion in olive oil in a large saucepan over medium-high heat, stirring constantly, until tender. Add the sliced carrot and garlic, and saute, stirring constantly, until crisp-tender. Add the chicken broth and the next 13 ingredients (up to the salt - leave out the noodles, reserved spinach, and yogurt). Bring to a boil. Partially cover, and reduce heat. Simmer 20 minutes or until the lentils are tender.
Stir in the reserved spinach and noodles; cook, partially covered, 7 minutes or until noodles are done. (Depends on the noodles you picked!). Remove and discard the bay leaf.
Ladle soup into individual bowls. Top each serving with a dollop of yogurt.