Bring stock to a boil in a nonreactive saucepan (do not use aluminum which will react with eggs which come into play later on).
Add bay leaf, sage, thyme and garlic cloves and cook, covered, at a bare simmer for 30 minutes.
Strain broth and discard herbs; pass and press garlic through to liquid and season to taste with salt. In a mixing bowl combine the cheese with egg and yolk, olive oil and pepper to taste. Everything can be done in advance up to this point.
Just before serving, reheat the soup and drizzle a ladleful of hot soup into the egg and oil mixture to temper the eggs. Pour this tempered mixture back into the soup and whisk continuously over low heat until the soup thickens slightly. Take care not to over heat or the eggs will curdle.
Set a piece of French bread crouton in center of soup plate and ladle soup over the top. Garnish with parsley.