Most Sundays from September to April I take the 44 bus to Enniskerry and walk up into the hills until my legs tell me to stop. There is a stretch above Lough Bray where the path goes on across the heather towards nothing in particular, and that is where I sit on my rucksack and open the flask. Nothing I have eaten in a restaurant has ever tasted quite as good as that first cup.
The soup is leek and potato, the plainest thing I know, and it is made the night before on purpose. A soup that has sat overnight in the fridge has settled into itself. The potato has thickened it, the leeks have gone sweet, and all you have to do in the morning is heat it until it steams and pour it into the flask while it is still too hot to drink.
What you need
For four flasks, or two flasks and two bowls at home:
- 3 large leeks, about 700 g before trimming
- 2 floury potatoes, Rooster or Maris Piper, about 400 g
- 1 small onion
- 40 g butter
- 1.2 litres of chicken or vegetable stock
- a bay leaf and a few sprigs of thyme
- 100 ml of whole milk or a splash of cream
- salt, white pepper, and a little nutmeg if you have it
How I make it
Trim the leeks, keeping as much of the pale green as is tender, split them lengthways and wash the grit out under the tap. Slice them thinly. Chop the onion small. Melt the butter in your heaviest pot over a low flame, add the leeks and onion with a good pinch of salt, put the lid on and leave them for fifteen minutes, stirring now and then. This is the slow part and the only part that matters. You want them soft and collapsed, with no colour at all.
Peel the potatoes and cut them into small cubes, about the size of a sugar lump, so they cook evenly. Add them to the pot with the bay and thyme, pour in the stock and bring it to a gentle simmer. Twenty minutes, uncovered, until a cube of potato falls apart when you press it against the side.
Fish out the bay and the thyme stalks. I blend about two thirds of the soup and leave the rest as it is, because a few pieces of potato and ribbons of leek are what make it feel like dinner rather than a drink. If you have no blender, a potato masher does a respectable job. Stir in the milk, then season: more salt than you think, white pepper, and the smallest grating of nutmeg.
The flask
Fill the empty flask with boiling water from the kettle while the soup reheats, then pour the water away and the soup in. A warmed flask keeps the soup properly hot for five or six hours, long enough for the slow walker I am. Leave a finger of space at the top so the lid closes without a fight.
I pack a heel of brown bread with it, a square of hard cheese and an apple. That is the whole lunch, and it has never once felt like too little.
If you are not walking anywhere
It is just as good on a wet Tuesday at the kitchen table. Fry a few cubes of stale bread in butter until they are crisp, scatter them over, and add a few chives from the windowsill if they have survived the summer. Next week: what the hedges along that same road give you in September, and a crumble to put it in.