Jansson's frestelse (jansson's temptation)

7 md Boiling potatoes; peeled &
           -cut into 2" X 1/4" strips
  2 1/2 tb butter
      2 tb Vegetable oil
      2 lg (to 3) yellow onions; thinly
           -sliced (4 cups)
     16    Flat anchovy fillets;drained
           White pepper
      2 tb Fine dry bread crumbs
      2 tb butter; cut into 1/4" bits
      1 c  Heavy cream
    1/2 c  Milk
 
  Preheat oven to 400øF.  Place the potato strips in cold water to keep
  them from discoloring. Heat 2 tablespoons of butter and 2 tablespoons
  of oil in a 10-12" skillet; when the foam subsides, add the onions
  and cook 10 minutes, stirring frequently, until they are soft but not
  brown.
  With a pastry brush or paper towels, spread a 1 1/2 to 2-quart
  souffl‚ or baking dish with the remaining half tablespoon of butter.
  Drain the potatoes and pat them dry with paper towels. Arrange a
  layer of potatoes on the bottom of the dish and then alternate layers
  of onions and anchovies ending with potatoes. Sprinkle each layer
  with a little white pepper. Scatter bread crumbs over the top layer
  of potatoes and dot the casserole with the 2 tablespoons of butter
  cut into bits. In a small saucepan, heat the milk and cream until it
  barely simmers, then pour over potatoes.
  Bake in the center of the oven for 45 minutes or until the potatoes
  are tender when pierced with the tip of a sharp knife or skewer and
  the liquid is nearly absorbed.