Lay the fillet of beef out onto a chopping board and use a very sharp knife to cut into ½ cm thick slices
Lay the circles of fillet out onto a sheet of greaseproof paper, leaving a 7cm gap between each piece. Place another sheet of greaseproof on top and use a rolling pin to roll out the pieces of beef to around 2mm in thickness
Remove the top sheet of greaseproof paper and lay 3 slices onto each plate, slightly overlapping to completely cover the base of the plate
Place the sheet of greaseproof over the sliced beef on the plate and use your thumb to flatten the beef out further. Repeat to flatten the rest of the beef
To prepare the garnish ingredients, cut the base off the treviso lettuce so you are left with individual curls of leaf. Dress with a dash of lemon juice and olive oil and a pinch of salt
Halve the fresh walnuts and set aside
Cut the gorgonzola into small pieces
Dress the beef carpaccio with some lemon juice, olive oil and salt and pepper. Use the back of a spoon to spread the dressing all over the beef to evenly coat
Scatter the dressed treviso leaves over the carpaccio, followed by the fresh walnuts, Gorgonzola and another drizzle of olive oil. Serve immediately
