Slow-Onion Jansson with Infused Cream and Butter Crumbs

Method

1. Heat the oven to 200 °C. Peel the potatoes and cut them into even sticks 4–5 mm thick with a mandoline or knife; equal thickness means even cooking. Don't rinse them; keep them in a bowl under a damp paper towel.

   Add in this stepFloury potatoes 500 g

   oven

2. Slice the onions thinly. Melt half the butter in a 22 cm pan over medium-low heat and cook the onions slowly for 15 min, until very soft, pale golden and sweet. If they start to catch, add a tablespoon of water and scrape the pan.

   Add in this stepYellow onion 1Butter 13 g

   medium-low heat

3. Put the cream, the garlic crushed with the flat of a knife, the bay leaf and the sprat brine in a 14 cm saucepan. Heat over medium heat until it bubbles at the edges, then take it off the heat and leave to infuse for 10 min. Watch it so it doesn't boil over.

   Add in this stepDouble (heavy) cream 180 mlGarlic cloves 1Bay leaf 1Brine from the sprat tin 2 tbsp

   medium heat

4. Chop the sprats roughly so their flavour spreads evenly. Butter a 20×15 cm baking dish lightly and layer potatoes, onions and sprats twice, finishing with potatoes; season with white pepper. Strain all the warm cream over, cover with foil and bake in the oven for 20 min.

   Add in this stepSwedish-style spiced sprat fillets (ansjovis) 70 gWhite pepper to taste

   oven

5. Melt the remaining butter and toss it with the panko. Remove the foil, press the potatoes down with a spatula so the cream rises over them, scatter the crumbs evenly and return to the oven for another 25 min, until the crust is deep golden and crisp and a knife slides easily through the potatoes.

   Add in this stepPanko breadcrumbs 4 tbspButter 13 g

   oven

6. Rest for 10 min so the cream settles, then scatter with chives and serve.

   Add in this stepChives, finely snipped 1 tbsp