Heat the oven to 350F and oil a 12 cup muffin tin generously, sides included.
Squeeze the thawed spinach in a clean towel until it stops giving water, then squeeze again. This step decides whether the bites set or weep.
Blend the eggs, cottage cheese, salt and pepper for a full 30 seconds, until completely smooth with no visible curds.
Divide the spinach and most of the cheddar between the cups, pour the egg blend over, and scatter the last cheddar on top.
Bake 20 to 22 minutes, until the centers are just set and barely domed. They deflate slightly as they cool; that is correct.
Cool 5 minutes in the tin before lifting them out with a thin spatula around each edge.