This is the easiest cheat-day recipe I know.
Make some béchamel sauce like mentioned in the lasagna recipe. (Butter, flour, milk, cheese, seasonings). Chop up whatever meats/veggies you might want for toppings, like bits of bacon or sausage or throw in olives or mushrooms.
Heat a tablespoon of oil in a pan. Take any sauced dry al-dente spaghetti and put it in the pan, and don't stir it or move it around; pour some sauce and toppings on top and then just let it sit there like a cake until the bottom browns and becomes crispy.
Put a lid on the pan and flip the pan so that the cake thing is now on the lid. Slide the frittata back in to let the other side fry. Let it cook and brown till you can move the entire thing around in the pan smoothly.
Slide it out onto a plate and serve with greens!