Butter a medium oven proof dish, mine measured 30cm x 20cm. Now make sandwiches using 8-10 Slices of Bread, this all depends on how thick your bread is, mine was quite chunky. I used Roasted Ham and Dijon Mustard in mine. Cut each sandwich into 4 and place haphazardly into the dish.
In a jug measure 400ml Milk and whisk in 3 Eggs and some chopped Chives. Pour this over the bread then scatter the top with 50g Grated Gruyere Cheese and a sprinkle of Parmesan.
Leave this to stand for 30 minutes so the egg can soak into the bread. Bake in the oven at 160C fan for 25-35 minutes till the liquid has gone and the top is golden and crusty.
You could add other bits of leftovers like chopped peppers, onions, leeks, tomatoes, salami, chorizo, sausages. We found that baked beans were the perfect accompaniment for this (as we had some).