Cut the slices into pieces approximately 8 -10 cm wide (2 inches).

Chop the onion, carrot and celery in a food processor, or get your good knife out and mince the vegetables.

Lay the slices of beef on a plate or chopping board.  Spread a few teaspoons of the vegetable mixture on them, then add a layer of prosciutto or cooked ham.

Starting from the narrowest end (if there is one) roll the beef slice up and secure it with a toothpick (or two if you're like me).  Repeat this process for all the slices of beef.

Heat olive oil in a frying pan on medium-high and brown the beef rolls on all sides.

Lower the heat to medium/medium-low and add the tomato puree, 1 tsp salt, and the bouillon cube.

Add water to just cover the rolatine and leave to simmer for about 20 minutes, stirring occasionally.

If the sauce is too watery at the end, turn the heat up to let the sauce thicken a little.