Heat the oven to 375 F.
Heat the oil in an ovenproof 10" skillet and cook the scallions and peppers, salting them lightly. Cook about 8-10 minutes, stirring, until softened.
While the vegetables are cooking, mix the eggs, milk and a pinch of salt together in a bowl. Add the bread cubes and soak them while the vegetables are cooking.
Lower the heat and pour in the egg, milk and bread mixture. Let cook 2-3 minutes without stirring.
Plop the spoofuls of ricotta around the top, then sprinkle the Parmesan cheese over it all.
Put the frittata in the oven and cook until done, about 15 minutes.
Take it out of the oven and let it rest a few minutes, then slide it out of the pan and cut into wedges.