1. Bring a large pot of water to a full boil. Remove the lid from the coddler, and lightly butter the inside of the cup. Break a large egg into the cup; if using a 6-oz. coddler, break two eggs into one cup.
2. Replace the lid, and be sure to fasten the metal clip securely on the lid and under the rim of the cup.
3. Use two forks to hold the coddler by its metal clip to lower it into the pot. The coddler should be fully submerged. Cook a single egg for 5 to 7 minutes, two eggs for 7 to 9 minutes. If you place two coddlers together in one pot, allow an additional 2 to 3 minutes cooking time.
4. Use the forks to remove the coddler from the water. To remove the lid, hold a folded kitchen towel over the coddler to protect your hands as you slide off the metal clip and remove the lid. Salt and pepper to taste, and serve immediately.