Set up: Preheat to 300°F and boil a kettle. Grease a 12-cup muffin tin thoroughly, right up over the top rim - egg sticks to anything you miss.
Blend the custard: Blend the eggs, cottage cheese, Gruyere, salt and pepper for 30-45 seconds until completely smooth and slightly frothy. No curds of cottage cheese should remain visible.
Fill the tin: Divide the turkey bacon and spinach between the 12 cups, then pour the egg mixture over. Fill only three quarters of the way up - they rise more than you expect.
Water bath: Sit the muffin tin inside a large roasting pan. Pour boiling water into the roasting pan until it reaches halfway up the outside of the muffin tin, then transfer to the oven. No roasting pan? Put a dish of boiling water on the bottom rack and the tin on the middle rack.
Bake: About 30 minutes, until the tops are set and only barely jiggle in the centre. They should be puffed and pale gold, not browned.
Remove within 3 minutes: Rest 3 minutes, run a thin knife around each, and lift out. They deflate slightly as they cool - that is normal. Left longer they keep cooking and start gripping the tin.