From Gourmet, September 2009
1/2 cup white-wine vinegar
1/2 cup cider vinegar
1 medium onion, thinly sliced
4 garlic cloves, finely chopped
1 tablespoon sugar
1/4 teaspoon cayenne
1 Turkish or 1/2 California bay leaf
4 1/2 pounds collard greens (about 3 bunches), stems discarded and leaves cut crosswise into 1-inch-wide strips
1 cup chopped (1/3 inch) fresh pineapple
Bring vinegars, onion, garlic, sugar, cayenne, bay leaf, and 1 1/2 teaspoons salt to a simmer in a small saucepan, then remove from heat and let steep 15 minutes. Discard bay leaf.
Meanwhile, cook collard greens in a large pot of well-salted boiling water until just tender, 6 to 8 minutes. Drain well in a colander, pressing to squeeze out excess water.
Transfer greens to a large bowl, then add pineapple and vinegar mixture and toss to coat. Cool to room temperature, tossing occasionally, about 1 hour.
NOTE: Pickled collard greens can be made 4 days ahead and chilled. Serve cold or at room temperature.