Sicilian Grilled Parmi-Reggi Prosciutto Sandwich

4 slices Sicilian bread
1 1/2 cups freshly grated Parmigiano-Reggiano cheese
freshly ground black pepper
4 slices prosciutto, thinly sliced
2 Tbsp unsalted butter

Put two slices of the bread on a work surface, divide the cheese in equal portions and cover the two slices of bread with a layer of the grated Parmigiano-Reggiano cheese. Coarse grind some black pepper over the top of this.

Now put two slices of the prosciutto on top then place the two remaining slices of bread on top. 
In a large frying pan (or panini maker if you have one), add butter and heat until it just becomes foamy. Add the sandwich, pressing into the pan and slowly fry until it becomes lightly browned; turn over and do the same on the other  side.

When bread is browned and cheese is melted, remove to a paper towel to drain and serve warm.