Heat oil in large saucepan over medium-high heat.

Add onions; cook, stirring frequently, for 8 to 10 minutes, or until translucent.

Add garlic; cook for 1 minute, or until tender.

Add turkey leg (if desired), bay leaves, thyme, salt, and pepper. Reduce heat to medium-low; cook, stirring occasionally, for 25 to 30 minutes, or until onions are a soft brown color.

Add wine. Bring to a boil over medium-high heat. Reduce heat; gently boil for 2 to 4 minutes, or until almost all liquid is absorbed. Remove turkey leg, bay leaves, and thyme.

Add broth. Bring to a boil over medium-high heat. Reduce heat; gently boil for 13 to 15 minutes.

Preheat oven to broil.

Place bread on a baking sheet; top with cheese. Broil for 3 to 4 minutes, or until cheese is bubbly and brown.

Evenly ladle soup into four serving bowls; top with bread.