My Swedish mother in law introduced me to this. For Sunday lunch this is what we had, with roasted vegetables. I made it early so I could enjoy the rest of the morning with the children, not cooking. So you can plan in advance and re-heat.
1 oz/25 g butter
1.7lb/800g waxy potatoes cut into matchsticks
8 anchovies roughly chopped and 100mls of their oil
1 onion thinly sliced (optional)
150ml single cream
100ml whole milk
Additional mix of 50mls of whole milk and 50mls cream (only add this if needed – see below)
Parmesan cheese to sprinkle liberally on top
1. Butter the dish.
2. Prepare the potatoes (I didn’t bother peeling them – up to you)
3. Mix the anchovies, oil, cream and milk with a little salt and pepper. Toss this with the matchstick potatoes. Place in the dish and sprinkle with parmesan cheese.
4. Place in the oven at 150 degrees C and after thirty minutes, if it not very creamy through evaporation, add the additional mix of milk and cream to the potatoes, pouring it on carefully in the gaps, so as not to cover the parmesan. If not, leave it.
5. Return to the oven and bake for a further 25 minutes or so until the potatoes are cooked through and the cheese is lightly browned.
Other examples of what to serve with this are a green salad or alongside lamb.