My Jansson’s Temptation

1.2 kg potatoes
400 g sliced onions
2 tins sprat fillets including brine
5 dl double cream
1 teaspoon kosher salt
1/2 teaspoons black pepper
1/4 cup breadcrumbs

2 tablespoons butter (divided)

1. Preheat the oven to 200°C.

2. Peel and thinly slice the onions. Sauté in 1 tablespoon butter on low heat in a frying pan until soft but not brown.

3. Grate the potatoes with the course side of the grater, no peeling necessary. rinse the shredded potato and squeeze ou all the water using a clean kitchen towel.

4. Blend the cream, anchoveys, salt and pepper, until smooth. 

5. Brush an ovenproof baking dish with butter.

6. Toss the potato and cooked onion together and place in the baking dish. 

7. Pour the cream mixture all over the potatoes.

8. Bake the casserole in the lower part of the oven for 50–60 minutes, until the potatoes are soft and golden brown.

9. When 10–15 minutes remain, take the Jansson out and sprinkle it with a thin layer of breadcrumbs that you mixed with a tablespoon of melted butter.

10. Put the casserole back in the oven and let the breadcrumbs turn golden. Then, let it rest for a while before serving.