or soup kettle, and add all the remaining ingredients. Bring to a boil, then reduce the heat and simmer, uncovered, for 1-1/2 hours. 2. Remove and discard the ham hock and bay leaf. Using a slotted spoon, transfer the bean mixture, in batches, to the bowl of a food processor. Process, adding cooking liquid as necessary to form a smooth, thick paste. You will use a total of about 1 cup liquid. 3. Transfer the pesto to a bowl and stir in the salt and pepper, if needed. Refrigerate, covered, until ready to use. This will keep in the refrigerator for 2 to 3 days. Makes 3 cups. Author's note: These beans make a hot and spicy spread. Also use them in place of the red bean paste in the Three Layer Mexican Dip, or serve them in fajitas or on nachos. Black Bean Pesto can also be heated through and served as a side dish, garnished with sour cream and cilantro.