Cullen Skink With Dill Oil
You know, I bet this would have been a really tasty soup if I hadn't spilled all the beautiful haddock, fennel, dill-stalk and shallot stock I'd just spent an hour preparing. Even so, using just milk and cream, it was pretty fine.
Cullen Skink with Dill Oil
soup fish
four medium sized potatoes
2 Arbroath smokies
1 fennel bulb
1 leek (optional)
2 bay leaves
6-8 small round shallots or 3-4 of the larger British Echalion "banana" variety + extra for the stock
splash white wine
bunch dill
walnut oil
white wine vinegar
milk, maybe a couple of pints
Serves 4

Put the potatoes in the oven to bake. This will probably take 1½ hours at Gas 6.
Slice off one of the smokie fillets to grill as a garnish later

Chop the fennel root, leek if you like and some shallots and place in a pan with the bay leaves and smokies, cover with water and a splash of white wine and set to gently poach for 4-5 minutes until the smokie is soft.
Take out the fish, carefully separate the flakes from the skin and bones and set aside.
The bones are quite small so this needs to be done rather carefully (Rachel!) or you'll end up with mouthfuls of them. Return leftover parts of fish to the stock to continue simmering.
I did try poaching the fish in milk here, but it ends up curdling it and you can't reduce it afterwards. Better I think to use water as traditional recipes suggest. Then strain and reduce the stock to add back to the soup later.

Meanwhile strip the feathery fronds from the dill and set aside to soak in a little white wine vinegar. Finely chop the rest of the shallots. You can throw the dill stalks and shallot offcuts into the stock as you work.
Use a hand blender to whizz up the vinegared dill with some walnut oil to make a thick green sauce. Season well.
I thought about using hazelnut oil for this, but it seemed like it would have too strong a flavour.
It might have been nice to blanch or otherwise cook the dill, rather than 'pickle' it, but it's a bit delicate to drop in boiling water I would think?
Actually - a quick blanch works just fine - deepens the flavour if anything.
Pat dry before blending with the oil. Season and then add a little white wine vinegar if you like.
Warning: Walnut oil goes off very quickly once opened if you don't refrigerate it and takes on a rather unpleasant fishy flavour, and I've had poor experiences with local Fucking Supermarket™ own-brand walnut oil which can come pre-aged and slightly rancid from new. So if you can't find a quality fresh walnut oil then substitute avocado oil, which also works well.

Strain the stock, then reduce it if desired (it's pretty tasty stuff).
Meanwhile simmer the shallots gently in enough milk to cover until they begin to soften. Mash the potatoes with a wad of butter when they're cooked. Stir the potatoes into the soup and distribute, finally add the flaked fish. Add more milk as necessary.
Finally add the hot reduced stock, but absolutely do not boil after this point or the milk will curdle. Stir in a little cream, and season to taste (it's probably already quite salty enough from the fish).

Grill the retained fillet until hot and glistening and carefully separate off the fish flakes.
Ladle the soup into bowls and decorate with pools of cream, dill oil and grilled fish flakes to make beautiful patterns.

Pretty damn fine. I thought the soup might have been better if a little runnier - so maybe go a bit easy on the cream, or the potato, reduce the stock less or some combination of the three.
Working with approximately equal quantities of mashed potato, flaked fish and chopped shallots seemed about right.
I suppose you could puree the potato and onion soup before adding the fish flakes if you fancy a smoother texture.

Instead of Arbroath Smokies you can go with more traditional Finnan haddies (lightly smoked haddock) - about 1lb or 1 large haddock.
You need to watch you don't overboil the haddie since it's already softer than the smokies, but it's a lot less fiddly since there's much less skin and bones in the Finnan haddie. I didn't think it tasted as good though, even though I still added an extra smokie just for the stock.

As I mentioned above, the soup will curdle like a bastard if you give it half a chance - which is a real shame because it spoils the lovely creamy consistency so absolutely do not boil it.
I made a half-decent stab at reconstituting my curdle by whisking it gradually into some fresh milk and butter, but it just wasn't the same. Sigh.