Celery Soup

Name: Celery Soup
Prep time: 15 min
Cook time: 40 min
Total time: 55 min
Cuisine: European
Ingredients: 2 butter pats; 2 tbsp olive oil; 2 garlic cloves, minced; 1 yellow onion, chopped; 1 head of celery, chopped and reserve leaves; 1 x 2 lb celery root, peeled and diced; 6 cups chicken broth; 4 sprigs thyme; 1 cup heavy cream; Salt and pepper