Slice half the onion thinly and let it wither in two tablespoons of extra virgin olive oil. Add the frozen peas and cook them well. Season with salt and pepper. With an immersion blender, puree the peas, keeping two or three tablespoons. Sieve the peas with a fine sieve. Set aside the pea cream. Drain the tuna from the oil. Put it in the blender with mozzarella, a little salt and pepper, creating a mousse. Roll out the very fine slices of beef, spread a little pesto alla genovese, half slice of processed cheese, half a slice of ham and roll up. Tie the rolls in a very hot pan, seal very quickly. Place them in an oven dish to let them cool. Roll out the slices of smoked salmon, tuna and mozzarella mousse. Roll them up and put them in blast chiller so that they solidify. In a non-stick pan, toast the slices of pancarrè previously cut with a round cookie cutter.