heat olive oil over medium-high heat in a Dutch oven; add onion, shallot, slivered fennel, salt and pepper, and cook until soft; add garlic, and bundle of thyme, and cook, stirring constantly, until very fragrant (about 1-2 minutes)
add chicken stock, beans, diced fennel, and parmesan wedges; simmer for about 30 minutes to blend flavors, stirring occasionally to lace the melting parmesan threads through the soup.
turn off heat; remove bundle of thyme, and give it a good shake over the soup to release any loose leaves, then discard; remove parmesan rinds, and set aside.
using an immersion blender, pulse the soup until about 1/2 of the beans are just barely pureed (be careful not to overblend, or your soup may become pasty)
stir in cream, and return parmesan wedges to soup; ladle into bowls, and top with ground pepper and fresh thyme leaves