A rich variation on the theme
6 slices bacon
1/4 pound sweet onion, sliced fairly thin
1/2 stick (1/4 cup) lightly salted butter
6 slices of square rye bread
12 lettuce leaves, washed and dried
3/4 pound goose liverwurst
freshly ground pepper to taste
finely chopped fresh parsley
1. Gently fry the bacon slices over moderate heat in a heavy sauté pan. Remove and drain on paper towels. Pour out all but 1 tablespoon of the rendered bacon fat, turn heat to high, and add the sliced onion to the pan. Sauté over high heat for 2 minutes, or until the onion just begins to turn brown. Remove onion and drain on paper towels.
2. Spread 1 teaspoon of butter on each of the bread halves. Top each half with a lettuce leaf that overlaps slightly on all sides. Spread about 1 ounce of liverwurst across each lettuce leaf. Cut the bacon slices in half, and top each smorrebrod with a half-slice of bacon. Divide the sautéed onion rings evenly among the 12 smorrebrod, top with freshly ground black pepper, and garnish each smorrebrod with parsley.
Liverwurst made with goose liver and goose fat works best for this smorrebrod, but regular pork liverwurst is also fine. If you cannot obtain the goose liverwurst, use a bit less of the more pungent pork product. Another possibility is a smooth liver pâté purchased from a delicatessen