Preheat the oven to 450 degrees

Heat 4 tablespoons of the olive oil in a large saucepan over medium heat. Add the onion, reduce the heat to low, and cook, stirring occasionally, about 15 minutes. Add the celery and cook about 5 minutes longer, stirring constantly.

Add the broth, chicken, bay leaves, salt, and pepper. Reduce heat and simmer about 1 hour, stirring occasionally.

Place both heads of garlic on a small sheet of aluminum foil and drizzle with 1 tablespoon of the olive oil. Wrap tightly and place in the oven to roast, about 35 to 40 minutes, or until the garlic is soft. Meanwhile, toss the mushrooms with the remaining olive oil in a baking dish, place in the oven, and roast 15 to 20 minutes, until golden brown, stirring once or twice during cooking to coat evenly.

Remove the mushrooms from the oven and add to the soup. Remove the garlic from the oven, peel the cloves, and add to the soup, leaving them whole.

Add the orecchiette to the soup and cook, stirring occasionally, 10 to 12 minutes longer, just until the pasta is al dente. Add the beans and heat through. Add the rosemary and parsley and stir to mix; remove from the heat.

Place a handful of spinach. Top with parmesan and serve immediately.