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A square serving of Jansson's Temptation on a grey ceramic plate garnished with a sprig of fresh dill.

Jansson's Temptation (Janssons Frestelse)

Sweden's legendary creamy potato casserole — layers of tender potatoes, buttery sweet onions, and spiced sprats baked in rich cream with a golden breadcrumb crust. Surprisingly unfishy, deeply satisfying, and completely impossible to resist.
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Prep Time 20 minutes
Cook Time 55 minutes
Total Time 1 hour 15 minutes
Servings: 6 people
Course: Dinner / Main Course
Cuisine: Finnish, Swedish
Calories: 420
Ingredients Method Notes

Ingredients
  

  • 2 lbs (900 g) russet potatoes, peeled and cut into ¼-inch (6 mm) matchstick strips
  • 2 large yellow onions, thinly sliced
  • 2 tins (3.5 oz / 100 g each) Swedish ansjovis (sprats in brine), fillets and brine reserved separately
  • 3 tbsp (45 ml) sprat brine (from the tins)
  • 1¼ cups (300 ml) heavy cream
  • 2 tbsp (30 g) unsalted butter, plus extra for greasing
  • 2 tbsp (15 g) fine dry breadcrumbs
  • ¼ tsp white pepper
  • Pinch of freshly grated nutmeg

Method
 

  1. Preheat the oven to 400°F (200°C). Generously butter a deep 9×9 inch (23×23 cm) baking dish and set aside.
  2. Cook the onions: Melt the butter in a skillet over medium-low heat. Add the sliced onions and cook, stirring occasionally, for 8–10 minutes until soft and translucent. They should be tender and lightly golden — not browned. Remove from heat.
    Thinly sliced yellow onions cooking in a skillet on a stovetop until soft and translucent.
  3. Prepare the potatoes: Peel and cut the potatoes into thin matchstick strips, roughly ¼ inch (6 mm) wide. Do not rinse them after cutting.
    Top-down flatlay of whole russet potatoes and matchstick-cut strips on a wooden board over a marble surface.
  4. Mix the cream: In a small bowl or measuring jug, combine the heavy cream and sprat brine. Stir in the white pepper and nutmeg.
  5. Layer the casserole: Spread an even layer of potato strips across the bottom of the prepared dish. Top with half the softened onions and half the sprat fillets. Add a second layer of potatoes, then the remaining onions and sprats. Finish with a final, even layer of potato strips.
    Top-down view of a baking dish layered with matchstick potatoes, sautéed yellow onions, and Swedish sprat fillets.
  6. First bake: Pour half of the cream mixture slowly and evenly over the casserole. Transfer to the oven and bake for 25–30 minutes.
  7. Add remaining cream: Remove the dish from the oven. Pour the remaining cream mixture around the edges and into any visible gaps. Scatter the breadcrumbs evenly over the surface and dot the top with a few small pieces of butter.
  8. Final bake: Return to the oven and bake for a further 20–25 minutes, until the top is deep golden brown and a fork slides through the potatoes with no resistance.
  9. Rest and serve: Allow the casserole to rest for 5 minutes before serving. Bring it straight to the table in the baking dish.

Notes

  • Swedish ansjovis ≠ regular anchovies. They are sprats in sweet spiced brine, not the salty, sharp Mediterranean kind. Find them at IKEA's food market or order online.
  • Do not rinse the potato strips — the surface starch helps the casserole hold together and creates a creamier texture.
  • Use full-fat heavy cream. Lower-fat alternatives will make the casserole watery and thin.
  • Make-ahead tip: Bake fully, cool, and refrigerate. Reheat at 325°F (160°C) with a generous splash of cream poured over the top.
  • Serving suggestion: Pairs beautifully with Swedish meatballs, pickled cucumber, lingonberry sauce, and a crisp green salad.