Heat the oil in an
8-quart pot over
medium heat. Add
onion and celery,
and cook until
softened. Add flour,
stir with a wooden
spoon until smooth,
and cook for 1 to 2
minutes. Add beer,
and then add all the
remaining
ingredients, adding
the greens by the
handful until all of
them are combined in
the mixture. Bring
the mixture to a
boil, reduce the
heat to medium-low,
and simmer,
uncovered, until the
hocks are very
tender, about 2
hours.
Remove the bay
leaves and serve
warm.
