Classic Jansson's Temptation

Preheat your oven to 200°C (400°F). Generously grease a 2-liter baking dish with a little extra butter to prevent sticking.

Melt the 60g of butter in a large skillet over medium heat. Add the thinly sliced onions and a pinch of the salt. Cook gently, stirring occasionally, for about 10-15 minutes until they are very soft, translucent, and sweet, but not browned.

While the onions cook, peel your potatoes. Cut them into thin, uniform sticks, similar to thick matchsticks or French fries. Rinse them thoroughly in cold water to remove excess starch, then drain and pat them completely dry with a clean kitchen towel.

Open the tins of Swedish ansjovis. Drain the oil and give the fish a rough chop—they will melt into the sauce, so don't worry about making them neat. Set them aside.

In a medium saucepan, combine the milk, double cream, and the remaining salt. Add the chopped ansjovis to the liquid. Bring the mixture just to a simmer over medium heat, stirring until the fish has mostly dissolved into the sauce. Remove from heat and season with black pepper.

Layer half of the dry potato sticks into the bottom of your prepared baking dish. Scatter the soft cooked onions evenly over the potatoes. Top with the remaining potato sticks.

Carefully pour the hot creamy ansjovis sauce over the potato layers, making sure it seeps down into all the gaps. If you like a crispy top, sprinkle the breadcrumbs over the surface now.

Bake uncovered in the center of the oven for about 90 minutes. The dish is done when the potatoes are tender when pierced with a knife and the top is golden brown and bubbling. Let it rest for 10 minutes before serving to allow the sauce to thicken slightly.