The ultimate tuna sandwich, on sourdough with peri-peri mayo

A tuna sandwich has a bad reputation, and it's mostly earned: wet bread, grey filling, too much plain mayo, nothing to bite on. The fix isn't complicated. Drain the tuna properly, use a mayo with some personality, add something sweet, something sharp and something crunchy, and put it all on bread that can hold its own.

I should admit up front that I came to this sandwich through failure. The first one I made for T to take to work, I didn't drain the tuna so much as wave it near a sieve. By lunchtime the bottom slice had gone see-through, and she sent me a photo of it from a bench near her office with no caption at all. A lawyer who doesn't bother with a caption is a lawyer building a case.

So I did what I always do, which is overthink it. I tried pressing the tuna with a fork, then with a potato ricer (works brilliantly, and you will be washing fishy ricer for a week), then with a clean tea towel. I tried three different mayos lined up in ramekins like a science fair. I timed how long a filled sandwich lasted in the fridge before the bread gave up. T watched most of this from the doorway eating the rejects, which is the arrangement in our house.

What came out of it is now our default work-from-home lunch, the thing that gets made on a Thursday when the fridge is down to condiments and good intentions. It also tastes a little like home to me. My mum used to mash tinned fish with raw onion, green chilli and a squeeze of lemon and eat it with rice, and I think this sandwich is just my British lunchbox brain arriving at the same place by a longer road.

Here, the mayo is Nando's Perinaise, a peri-peri mayonnaise you'll find in most UK supermarkets. Any peri-peri or chilli mayo works, and so does plain mayo with a pinch of chilli flakes and smoked paprika. The bread is a sturdy sourdough such as Jason's, which has a chewy crumb and a crust that doesn't go soggy the moment the filling arrives.

For the record, nobody is paying us to say any of that. No freebies, no affiliate links. We buy the Perinaise and the bread from the supermarket like everyone else, usually alongside a bag of onions and whatever T has decided is a snack this week.

What makes it work

• Dry tuna. Press out as much liquid as you can. Watery tuna is the main reason sandwiches go soggy.
• A mayo with heat. Peri-peri mayo brings chilli, garlic and a bit of acidity, so the filling tastes seasoned rather than just creamy.
• Sweetness and crunch. Sweetcorn adds pops of sweetness, while spring onion and red onion add bite.
• Lemon and black pepper, to lift everything and stop it tasting flat.
• A thin layer of mayo spread right to the edges of the bread. It acts as a barrier, which helps if you're packing it for later.

Ingredients (makes 2 sandwiches)

• 4 slices of sourdough, about 1.5cm thick (Jason's or any good sourdough loaf)
• 2 × 145g tins of tuna in spring water or brine (about 200g drained), drained very well
• 3 tbsp Nando's Perinaise or another peri-peri mayo, plus about 2 tsp for spreading
• 4 tbsp sweetcorn (about 80g), drained and patted dry
• 1 spring onion, finely sliced
• 1 tbsp very finely chopped red onion (optional)
• 1 to 2 tsp lemon juice, to taste
• Plenty of freshly ground black pepper
• Salt, to taste (go easy if your tuna is in brine)
• ¼ cucumber, thinly sliced and patted dry (optional)
• Crisps, to serve

Method

1. Drain the tuna. Tip it into a sieve and press it firmly with the back of a fork until no more liquid comes out.
2. Make the filling. In a bowl, mix the tuna, 3 tbsp peri-peri mayo, sweetcorn, spring onion and red onion (if using). Keep some texture: you want flakes, not paste.
3. Season. Add 1 tsp lemon juice and a good grind of black pepper. Taste, then add more lemon, pepper or a pinch of salt if it needs it.
4. Prepare the bread. Toast the slices lightly if you like (see below), then let them cool for a minute so the steam doesn't soften them. Spread a thin layer of peri-peri mayo right to the edges of each slice.
5. Build. Lay the cucumber on two slices, pile the tuna filling on top and spread it almost to the crust. Top with the other two slices, mayo side down.
6. Press gently with your palm, then cut each sandwich in half diagonally with a sharp serrated knife. Serve with crisps on the side.

What we changed along the way

Three tablespoons of peri-peri mayo for two tins of tuna is where we landed. We started at four, and it was lovely for exactly two bites, then it turned into a mayo sandwich with some tuna in it. Three keeps the filling creamy but still flaky. We use the medium heat; the hot one is good, but it bullies the lemon and the spring onion out of the picture.

The red onion stays, but only if you chop it properly fine. My early versions had chunky bits that you'd still be tasting at four o'clock. If you're nervous about raw onion, rinse it under the cold tap for a few seconds and dry it, and it calms right down.

The cucumber is where we split. T likes the cold crunch. I think it's a liability, because even patted dry it leaks a little, so in my sandwich it goes on the side with the crisps. It's marked optional because we couldn't agree, which is honestly how half our recipes get their optional ingredients.

The thing that surprised me most was the lemon. It's only a teaspoon, and it doesn't make the filling taste lemony. It just makes it taste finished. Leave it out once and you'll see what I mean: everything goes slightly flat and beige, like a meeting that could have been an email.

Toasted, or not?

Lightly toasting the sourdough gives you a crunchy outside and stops the filling soaking in, which matters if you're not eating it straight away. Untoasted sourdough is softer and chewier. Both are good, and the method works either way.

On a cold Sunday, though, it's the tuna melt below, and nobody argues. The peri-peri mayo goes soft and warm into the cheese and the sweetcorn catches a little at the edges. It's the one version T asks for by name.

Hot version: tuna melt

• Build the sandwich with untoasted bread and add 40g grated mature Cheddar per sandwich on top of the filling.
• Lightly butter the outsides of the bread.
• Cook in a dry frying pan over a medium-low heat for 3 to 4 minutes a side, pressing down gently with a spatula, until the bread is golden and the cheese has melted. Keep the heat moderate so the bread doesn't burn before the middle is hot.
• Rest for a minute before cutting. Melted cheese is very hot.

Swaps and extras

• Not a fan of sweetcorn? Swap it for finely diced celery or a few chopped cornichons.
• Want more heat? Add sliced pickled jalapeños or a finely chopped green chilli.
• Want it milder? Use a mild peri-peri mayo, or mix half peri-peri mayo with half plain mayo.
• For extra crunch, add a handful of crisp lettuce or a few crisps inside the sandwich. It's a classic for a reason.
• For more freshness, add a little chopped fresh coriander or dill to the filling.

Our crisps are a running disagreement. I want salt and vinegar, the sharp kind that makes your eyes water slightly, because the vinegar does the same job as the lemon. T wants plain ready salted, and she wants them inside the sandwich, pressed in at the last second so they crack when you bite. I used to think that was chaos. I now do it too, and I'd prefer not to discuss it.

When we want it to taste more like my mum's version, we add one finely chopped green chilli and a small handful of chopped coriander to the filling, and swap the lemon for lime. It's a different sandwich, louder and greener, and on a grey London afternoon it's the one I reach for.

Keeping it safe

• Don't keep leftover tuna in an opened tin. Move it to a covered container, refrigerate it and use it within 2 days.
• Keep the made-up filling in the fridge, covered, and eat it within 24 hours.
• If you're packing the sandwich for lunch, keep it cold in an insulated bag with an ice pack and eat it the same day. Don't leave it out at room temperature for more than a couple of hours.
• Pregnant? The NHS advises limiting tuna to no more than 4 medium-size tins (about 140g drained each) or 2 fresh tuna steaks a week, because of mercury. Check the current NHS guidance.
• For a tuna melt, eat it straight away while it's hot. Don't reheat it.

That's it. Ten minutes, one bowl, a sieve you'll want to rinse straight away. Drain the tuna like you mean it, and if anyone sends you a photo of your sandwich with no caption, you'll know which step you skipped.

Cook it with Jan

Want to make tuna, sweetcorn and peri-peri mayo sourdough sandwich tonight? Jan will scale it for your crowd and walk you through every step.

Let's cook!

• Sandwiches
• Quick lunch
• Packed lunch
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• 10-minute meals