Tramezzino Tonno e Pomodoro

In a Milanese bar in July the case has a row of triangles labelled tonno e pomodoro in green pen, and the cook behind the counter is replacing them at lunch with a fresh row built that morning. The summer tomato is what makes that turnover necessary. Inside the triangle the tuna and mayonnaise lie as a pale spread along the lower slice; on top of the spread, a single ripe tomato disc shows red across the cross-section. The slice arrives with a sweet juicy lift the bound spread can never produce on its own, a vegetal cold cut against the rich mass below it, and the cellophane case behind the glass exists in part to slow the moment that lift starts to cost the bread.

The tomato is doing one job and threatening another. The job is brightness. A tomato slice introduces a cool sweet acidity that the spread lacks; it also gives the cross-section the only colour in the case. The threat is water. A ripe summer tomato is heavy on cellular fluid, and that fluid runs into the cut face within minutes of the knife. Left there, it greys the pancarrè it touches; sealed away, it gives the bite its only fresh element.

The save is in the slicing and the order of operations. The tomato is picked ripe and firm, not soft, the inner pulp and seed mass scooped out with a teaspoon along the cross-section, and the wall slices that remain are laid on a paper-lined board and salted lightly. The salt pulls a little juice within two or three minutes; the slices are then blotted between two cloths until the surface is matte and the paper underneath turns no further pink. The fish is folded with a touch less mayonnaise than for the plain version, because the slice will bring its own moisture even after blotting, and the firmer spread can take that. The spread is laid first against both inner crumbs, then the slice sits centrally on the lower face. The mayonnaise underneath films the bread; the spread above shields the upper face. The slice is bracketed by fat on both sides.

The losses are specific. A tomato sliced too thick puts a wet slab against the bread and the lower face goes pink within the hour. A tomato seeded badly leaves the watery pulp in place and the disc weeps even after salting. Skipped salting and the slice carries its full water load into the cross-section. A tomato that is bland and underripe brings no sweetness to weigh against the rich spread, and the build reads as soggy fish with a pink disk through it. A working version uses the day's ripest firm tomato, seeds and salts and blots, lays the slice into the fat seal, and gets the wrapper on within five minutes of assembly.

The bar grammar around it is short. The triangle is asked for at the case as tonno e pomodoro, never tomato tuna sandwich; the cook lifts it off its tray with metal tongs and onto a paper saucer, and a half-glass of white from the case sits beside it. In Trieste the same triangle picks up a leaf of rocket and becomes tonno, pomodoro e rucola. In Verona a few capers go through the spread to push back against the sweetness of the tomato. In Naples the same idea is built on a panino con tonno e pomodoro, in a soft sesame roll, and stops being a tramezzino at all. The Italian bar's set of two-ingredient additions to the base, each named in green pen on the saucer card, runs to about a dozen, of which this one is the most common in summer.

The closest relatives in the case each go their own way. The disc sliced thinner and replaced with a leaf of lettuce gives a different lift, drier and bitter, with no moisture problem. The disc replaced with a marinated artichoke quarter gives a cured edge and a fully different sandwich. The disc dropped entirely returns the triangle to the unadorned baseline. Each of those is read against this build, and this build is read against the season: outside July to September a Padua bar will tell you the tonno e pomodoro is on hiatus until the market gives them tomatoes again.

Origin and history

The triangle itself was first cut at the Caffè Mulassano, the marble-clad bar on the Piazza Castello side of Turin, in 1925. Angela Demichelis Nebiolo and her husband Onorino, two returned Piedmontesi who had run restaurants in Detroit, had bought the room that year and brought back an American pull-toaster and a habit of trimming crusts off soft white bread. Gabriele D'Annunzio christened the form a few seasons later, and La Cucina Italiana printed the first national recipe in July 1936.

The tomato-and-fish version is a later post-war filling, one of the case additions that arrived with the canned-tomato boom and the wider availability of oil-packed tuna across northern Italy in the 1950s. It is not in the 1936 list. It belongs to the case of the modern Italian bar, where the cook stocks a row of about a dozen named two-ingredient additions to the base every morning and replaces the wettest of them, this one, twice a day in summer.

The form's anchor remains the Torino caffè. Mulassano still stands on Piazza Castello 15 and still serves a row of small crustless triangles from the marble counter, and the tonno e pomodoro is among the named fillings on the saucer card a hundred years after the room first cut its first crust off.