Heat the oven to 350F and oil a 9 inch pie dish or 8 inch square pan.
Saute the onion and bell pepper in the oil until soft and their moisture has cooked off, about 8 minutes. Wet vegetables are the crustless quiche's only enemy.
Squeeze the thawed spinach in a clean towel until it stops giving water, then squeeze again. Break it apart into the pan for a final minute.
Blend the eggs, cottage cheese, salt and pepper until completely smooth, about 30 seconds.
Layer the vegetables and most of the cheddar in the dish, pour the egg blend over, and scatter the last cheddar on top.
Bake 35 to 40 minutes, until the edges are golden and the center barely jiggles when nudged. Rest 10 minutes before cutting into six.