Rachel Roddy’s recipe for rocket, leek and potato soup

Rocket. What a wonderful name for a leaf. Wild rocket is even better, suggesting an untamed missile of heat and flavour. It was a bit disappointing, then, to find out the name has nothing to do with space travel or fireworks, but comes from the French roquette, diminutive of the Latin eruca, which – according to my dictionary – was originally an early variety of cabbage. Like cabbage (and broccoli, sprouts, kale, radish, turnips, mizuna, horseradish and watercress), rocket is part of the brassica, crucifer or mustards family, all with their different degrees of heat and pepperiness. Rocket is the higher end of the scale, the rascal of the salad bowl.

I found my first leaf of rocket in a salad in Pizza Express on Coptic Street in central London when I was about 13. As if the place, with its white tiles, tiered topping station, Italian waiters and dough balls wasn’t exciting enough, there were hot leaves under the special house dressing. A few years later, when Pizza Express expanded to the home counties like middle-age spread, my brother would work there and we’d learn the secret of the house dressing, which I am sure had changed by then, so it was doubly disappointing. Back to the leaf at 13, though, which wasn’t disappointing. It was saw-edged, peppery and as Italian as the waiter.
Eruca sativa has grown in the Mediterranean since Roman times, when it was considered an aphrodisiac. Nowadays, Italians have at least six names for this much-loved peppery leaf – ruga, arugula, rucola, ricola, ruchetta, rughetta. In Rome, it is generally rughetta and either domestica (cultivated) or selvatica (wild) – which, contrary to expectation, is often milder tasting.
As much as I like it, I don’t want rocket everywhere. Some sandwiches and salads are better off without. Rocket works well in a mix of leafy but mild-mannered and bitter leaves. It is even better tangled round small, sweet tomatoes or with parmesan – as my partner says, “the dreaded shavings” – and especially with seared strips of beef, which make the rocket wilt. In Puglia, rocket is mixed with tomato sauce at the end of cooking to eat with pasta. I also enjoy it cooked – as so many green vegetables are in Puglia – with olive oil, garlic and chilli, also for pasta.

Then there is soup. This is a meeting of two of my favourites: leek and potato, and watercress, with rocket standing in as the leafy green. It’s a standard recipe to start. Then, my bit: some rocket pesto to add to the soup in the last minutes of cooking. This isn’t blobbing a neat garnish on top; it is stirring a good amount of rocket puree into soup, which makes it speckled and insistently, brilliantly green. It also means two layers of rocket: some cooked along with the leek and starchy potato; the rest a bright, peppery, almost raw, rocket chaser at the end.

Rocket, leek and potato soup
Prep 10 min
Cook 40 min
Serves 4

2 bunches of rocket (about 100g)
8 tbsp olive oil
1 onion, diced
1 large leek, sliced
Salt and black pepper
2 potatoes (about 500g), diced
1 bay leaf
1.2 litres water or vegetable stock

Pick over the rocket and trim away any tough stems, then divide in two.

In a large, heavy-based pan, gently fry the onion, leek and a pinch of salt in four tablespoons of olive oil until soft and translucent. Add the potato and stir until every cube glistens, then add the bay leaf and half the rocket and stir again.

Add 1.2 litres of water or stock to the pan and another small pinch of salt, bring to a boil, then reduce to a simmer for 25 minutes, until the potato is soft and collapsing at the edges.

In a blender, blitz the second bunch of rocket, the remaining four tablespoons of oil and a pinch of salt to a coarse puree and add it to the soup in the last two minutes of cooking. Taste and add a bit more salt if it needs it and a few grinds of black pepper. Serve with bread.