Heat the olive oil in a large soup/stock pot. When hot, add the onion and garlic and cook over moderate heat until the vegetables have softened and begin to brown.
Add the water, the Parmesan rinds, thyme, parsley, bay leaf, and peppercorns.
Bring to a simmer. Simmer, partially covered, for at least an hour, up to 2 hours.
Strain the broth.
