|2 pounds turnip greens, tough stems discarded and
greens torn into small pieces
1 (¾ -to 1lb.) ham hock, rinsed
3 1/2 cups water
1 1/4 pounds turnips, peeled and cut into 1/2-inch pieces
2 teaspoons cider vinegar
2 teaspoons sugar
2 tablespoons unsalted butter, cut into pieces
Bring greens, ham hock, water, and ¼ teaspoon salt to a boil in a large heavy pot.
Reduce heat to low and simmer, covered, stirring occasionally, until greens are almost tender, about 20 minutes.
Meanwhile, peel apples and cut into 1/2-inch pieces.
Add turnips and apples to greens with vinegar, sugar, and 1/2 teaspoon each of salt and pepper and cook at a bare simmer, covered, stirring and turning ham hock occasionally, until turnips and apples are tender but not falling apart, about 20 minutes more. Remove from heat and stir in butter and salt to taste.
Remove ham hock and finely chop any tender meat, discarding skin, bone, and tough meat. Add chopped meat to pot.