This is a family favorite at my house and has a multitude of variations.
-250 ml grated parmigiano reggiano
-225 g frozen peas, defrosted*
-1-2 yellow onions, diced and sauteed in olive oil until golden, salt and pepper to taste.
-100-150 grams of good salami, traditionally sopressata**, diced
-1 small mozzarella in water, thinly sliced***
-2-3 slices of country bread
-2 cloves garlic
Tear bread into pieces and whirl in a food processor with the garlic until you have a large cupful of bread crumbs. Briefly saute the crumbs in olive oil until the crumbs are slightly golden and the garlic no longer smells raw, salt and pepper lightly.
Carefully fold half the peas, the PR and the salami into the mashed potatoes. Spread half the new mixture into a deep baking dish around 8″ x 6″. Spread the onion mixture on top of the potatoes, then the remaining peas and finally the slices of mozzarella. Cover again with the remaining potato mixture and finally with the bread crumbs.
Bake in a 175c ventilated assist oven, 200c/400F oven for 30 minutes until the potatoes begin to bubble.
* You can substitute other vegetables like cooked broccoli in place of the peas although they are traditional. I have also seen sliced hard boiled eggs in place of the vegetables.
**This dish rises or falls on the quality of the salami. In the US I always used Genoa salami which does not exist in Italy. Here I would use the best quality local salami you have or your favorite. You could also use Spanish chorizo which I used tonight, or Portuguese linguica.
***You can substitute scamorza for all or part of the mozzarella.