Sort the beans to make sure they are free of stones or other debris. Rinse, then cover with cold water, refrigerate, and soak overnight.
The next day, drain the beans, place them in large pot, and cover with the stock. Bring to a boil, then lower the heat and simmer the beans for 2 hours, or until they are soft, tender and yield to pressure when squeezed between your finger tips.
Add the salt only in the final 15 minutes of cooking since the addition of salt earlier in the cooking process will result in tough beans.
Pour the beans in to the bowl of a food processor. Begin to pulse the beans along with any of the stock that may have remained from cooking. Add all the remaining ingredients except the truffle oil and pulse together with the warm bean puree. Taste and adjust the seasoning with additional salt and add freshly ground pepper if needed. Return the bean puree to a pot set over low heat or a double boiler to keep warm. Serve each portion of puree with a drizzle of truffle oil.