Preheat the oven to 200°C conventional oven/ 180°C fan-forced (400° Fahrenheit/Gas 6). Line a large baking tray with baking paper. Pour enough canola oil to generously cover the base of the paper-lined baking tray.
Place 20g of the breadcrumbs in a large bowl and pour the milk over to soak for a few minutes. Break up the sausage meat with your hands and add it to the bowl with milk-soaked breadcrumbs. Add the beef mince (ground meat), 1 egg, half of the Parmigiano Reggiano and chopped parsley. Season well with salt and pepper, then use your hands (or you may wish to use disposable gloves) to mix until well combined.
Place a large rectangular piece of baking paper on a clean work surface. Rub extra virgin olive oil over the baking paper. Spoon the meat mixture onto the baking sheet. Use a metal spoon to press the meat mixture into a large rectangle shape that is approximately 1cm thick throughout. Arrange the ham evenly over the meat mixture, leaving a 2cm border around the edges. Top the ham with the thinly sliced mozzarella.
Use the baking paper to roll the meat mixture from the short end to enclose the ham and mozzarella cheese filling. Refrigerate for 1 hour.
Remove the rolled meat mixture from the fridge and place onto a chopping board. Remove and discard baking paper. Slice the meat mixture into 2cm thick involtini rounds.
Use a fork to lightly whisk 2 eggs in a shallow bowl. Combine the breadcrumbs and remanining Parmigiano Reggiano in a separate bowl. Dip one of the mince-meat involtini in the egg mixture, then completely coat in the breadcrumbs. Place the crumbed mince-meat involtini into the prepared baking tray. Repeat with the remaining involtini.
Bake for 20 minutes, turning half way through cooking or until the crumbed mince-meat involtini are browned and cooked through – buon appetito.