This recipe from Josh Russ Tupper of Russ & Daughters is used to make his Oy Vey Schmear sandwich.
Source: The Martha Stewart Show, March 2009
Yield Makes enough for 3 pounds chopped liver
1 pound Vidalia onions, each cut into eights
1 tablespoon vegetable oil
3/4 teaspoon sugar
Place onions in a medium skillet, along with oil and sugar. Place skillet over low heat and cover with a parchment paper-lined aluminum foil round. Cook, stirring every 10 minutes, until onions are caramelized, 15 to 20 minutes.