Peel the rosemary leaves off the woody stems.
Finely mince the rosemary.
Peel the shallots.
Mince the shallots.
Saute the shallots and the rosemary in the oil.
Peel the yams and slice into rounds. Add to the shallots and toss to coat. Add the stock, adjust seasoning, and bring to a boil. Cover and simmer for about 10 minutes.
Add the cream. Optionally, you can add some fresh nutmeg at this point.
Simmer until the yams are tender and the sauce has thickened.
Adjust seasonings again and serve.