My bank records reveal that in the past year I’ve made more than a dozen transactions at Rooster Bar, a no-frills chicken shop that’s been in Fairfield for more than two decades.

But not once have I ordered rotisserie chicken. “That used to be more of the focus,” says owner Theo Liolios. “But as the burger trend took over Melbourne – and Grill’d opened next door – we transformed into selling more burgers than we do chickens a week.”

What I’ve become unable to live without is the chicken-fillet burger, on the menu since day one but tweaked over the years into the magnum opus it is today. Between it and its chicken-schnitzel counterpart, also delicious, Liolios sells about 2500 a week.

And, technically, it’s more sandwich than burger (plus by definition, a burger has to have a minced-beef patty), which I’m happy to report qualifies it for this instalment of Sandwich Watch, a column dedicated to the Melbourne sandwiches you need to know about.

It’s a four-ingredient meal

All that’s involved is a round roll from Thomastown pita producer Mr Pitta, a chicken-breast fillet, a handful of shredded iceberg lettuce and a hit of whole-egg mayo.

So, why does it hit so hard?

In an era when sandwiches often do the most, comically overstuffed to make a splash on social media, those that confidently do the least are sometimes the most impressive. “We really try not to do too much, making it a good entry point,” says Liolios.

By keeping it simple, he’s able to keep the price down. This may be the best $10.50 I’ve ever spent, especially since you could easily pay twice as much for a sanger half as good elsewhere.

The chicken is the star

Rooster Bar gets in whole La Ionica chickens, firing some on the charcoal rotisserie and breaking down others, using breasts for the fillet (and schnitzel) burgers. They’re marinated in a blend of 15 herbs and spices, a secret Liolios guards with his life.

The cooked-to-order fillets are always juicy. And while they taste charcoal-fired they’re actually done over a gas grill “with some Heat Bead tricks”, Liolios says.

But the bread (nearly) steals the show

Pudgy pita-esque rolls are twice-heated – first in the toaster for warmth, then on the grill for char – before it’s filling time. They’re not too flimsy, not too firm. And what Liolios loves about them is “they soak up all the flavours without making it too heavy”. The chicken’s own juices combine with a good amount of store-bought whole-egg mayo (given a “slight adjustment to add a slight tang to it”, he says) to lightly coat the iceberg.

And the best part?

Sandwiches can be situational: some are best suited to a healthy weekday lunch, others are hangover-busting beauties. But this one feels like a true everyday sandwich. It’s wholesome but hearty. There’s protein, there’s freshness. It travels tremendously well.

And generously chicken-salted hot chips are just waiting to be added to your order.

How do I get one?

The chicken fillet burger ($10.50) is available at Rooster Bar, 128 Station Street, Fairfield, daily from 10.30am to 8pm.

This is the latest instalment of Sandwich Watch, a column dedicated to the Melbourne sandwiches you need to know about.

Good Food reviews are booked anonymously and paid independently. A restaurant can’t pay for a review or inclusion in the Good Food Guide.