The legendary Harry’s Bar in Venice serves utterly perfect finger sandwiches that have been imitated and perfected all over the world (Truman Capote was said to be a big fan).

No one nails these fluffy white bread treats better than Fatto Bar & Cantina at Melbourne’s Hamer Hall. With its Yarra River frontage overlooking rowers and ferries, you might kid yourself that you’re on the Grand Canal.

Fatto head chef James Kummrow showed The New Daily how to make the distinctive, hump-shaped sambo at home.

What you’ll need

King prawns
Sliced white bread
Baby cos lettuce
Fresh tarragon
Homemade mayonnaise
Softened butter
Lemon juice
Salt and pepper

Step one – it’s all in the mayo

Make sure you make you own mayo, either by hand with a whisk in a metal bowl (the labour intensive way), or in a food processor.

Take 1 free range egg yolk, 1 tablespoon of Dijon mustard, 15 ml of white wine vinegar (preferably chardonnay vinegar) and a pinch of salt.

Gradually drizzle in 250 ml of vegetable oil and combine vigorously until the mayo emulsifies into a firm, decadent sauce.

Step two – prawn it

Peel and de-vein 700 grams of king prawns and poach in salted boiling water until just pink (3-4 minutes). Remove from the water, cool and dice the flesh.

Step three – mix it

Combine the mayo and cooked prawns with finely chopped tarragon. Season with salt, pepper and a squeeze of lemon.

Step four – butter it

Spread thick slices of fresh white bread evenly with softened, unsalted butter on one side of both slices.

Step five – assemble it

Place shredded, washed cos lettuce along one of the slices, leaving a 2 cm margin of bread on either side.

Top with prawn/mayo mix (a piping bag works wonders).

Step six – seal it

Cover with the other slice of bread and press down firmly on the edges with the back of a knife to create the distinctive bridge-shaped seal.

Don’t be afraid to exert a little pressure.

Step seven – serve it

Trim the crusts and cut in three.

Drizzle with a little olive oil and serve immediately.

Harry’s Bar prawn sandwiches at Fatto Bar & Cantina, 100 St Kilda Road, Melbourne, call (03) 8698 8800.