In a 4-quart saucepan, bring the water and smoked turkey to a boil over high heat. Reduce the heat and simmer, covered, for 1 hour.
While the turkey is cooking, wipe the collards with a damp towel, then wash 2 or 3 times or until all the dirt and grit has been removed. Chop the greens into 1/4-inch pieces; you will have 10 cups of chopped greens.
Add the collards, oil, salt, black pepper, sugar and red pepper flakes to the saucepan. Return to a boil, reduce the heat and simmer, covered, for 30 minutes longer. Discard the turkey before serving, or chop the turkey meat and add it to the collards.
Recipe courtesy of B. Smith