Janssons Frestelse

Ingredients

• 3⅓ lbpotatoeswaxy, peeled and cut into thin matchsticks
• 6onionsmall to medium, peeled and thinly sliced
• 20anchovy filletstinned, reserve the brine; if salt-packed, rinse and pat dry
• 2⅛ cupscreammixed with the anchovy brine
• 2¾ ozbutterfor softening the onions, greasing the dish and dotting on top
• 3 tbspbreadcrumbsfor sprinkling on top
• saltsparingly, the anchovies are salty
• black pepperfreshly ground
• 1 bunchdillsprigs for garnish (optional)
• 1lemonunwaxed, cut into eighths for serving (optional)

Method

1. Prepare oven and anchoviesHeat the oven to 390 °F. Open the tins of anchovies, pour the brine into a bowl and set the fillets aside. If you're using salt-packed anchovies, rinse them briefly and pat them dry instead.
2. Slice onions and potatoesPeel the onions and slice them thinly. Peel the potatoes and cut them into thin matchsticks.
3. Soften the onionsMelt some of the butter in a frying pan and cook the onions over medium heat until soft.
4. Layer the gratinButter a baking dish. Layer the potatoes, onions and anchovy fillets, seasoning each layer with pepper and only a little salt, as the anchovies are salty. Finish with a layer of potatoes.
5. Pour over the creamStir the reserved anchovy brine into the heavy cream and pour it evenly over the dish.
6. Top with crumbs and butterScatter the breadcrumbs over the top and dot with the rest of the butter.
7. Bake until goldenBake in the middle of the oven for 45 to 60 minutes, until the potatoes are tender and the top is browned.
8. Garnish and serve hotServe hot, with sprigs of dill and lemon wedges if you like.

Tips and variations

You can also bake it at 175 °C, adding the heavy cream in two parts (the rest after 45 minutes), leaving out the breadcrumbs and garnishing with dill and lemon wedges. For a vegetarian version, use soaked arame seaweed instead of anchovies and oat cream spread between the layers. To make it vegan, swap the anchovies for capers, the heavy cream for oat cream and oat milk, and the butter for vegan margarine; in this version everything is mixed together in a bowl rather than layered. On a buffet, serve it straight from the dish so everyone can take a piece with some of the crisp crust.