The basic principle of egg cooking is to use a medium to low temperature and time carefully. When you cook eggs at too high a temperature or for too long at a low temperature, the whites shrink and become tough and rubbery and the yolks become tough and their surface may turn gray-green.
To kill bacteria and other microorganisms, the recommended guidance is to cook eggs until the whites are firm and the yolks thickened. Cook egg dishes to an internal temperature of 160ºF (71ºC). Pasteurized shell eggs are available on the market for those who prefer eggs not cooked to this level of doneness. There are five basic methods for cooking eggs.
Eggs baked in a dish in the oven, also known as shirred. Break and slip 2 eggs into a greased 10-ounce custard cup, shallow baking dish or ramekin. Spoon 1 tablespoon milk or half and half over the eggs. Bake in a preheated 325ºF (163ºC) oven until the whites are completely set and the yolks begin to thicken but are not hard, about 10 to 12 minutes, depending on the number of servings you’re baking.
Hard-Boiled / Hard-Cooked
Place eggs in a saucepan large enough to hold them in a single layer. Add enough cold water to come at least 1 inch above the eggs. Heat over high heat to boiling. Turn off heat. If necessary, remove the pan from the burner to prevent further boiling. Cover pan. Let the eggs stand in the hot water about 12 minutes for large eggs (about 9 minutes for medium, about 15 for extra-large). Immediately run cold water over the eggs or place them in ice water until they're completely cooled. Never microwave eggs in the shell and unfortunately, it’s almost impossible to hard-boil eggs at altitudes above 10,000 feet.
– See Peeling
For Sunny-Side-Up Eggs: Heat a small amount of butter in a nonstick skillet over medium-high heat until hot. Break eggs and slip into pan, one at a time. Immediately reduce heat to low. Cover pan and cook slowly until whites are completely set and yolks begin to thicken but are not hard, 5 to 6 minutes. Sprinkle with salt and pepper.
For Over-Easy or Over-Hard Eggs: Cook as for Sunny-Side-Up, but do not cover pan. When whites are completely set and yolks begin to thicken but are not hard, 5 to 6 minutes. Slide turner under each egg and carefully flip it over in pan. Cook second side to desired doneness, 30 seconds to 1 minute.
For Basted Eggs: Cook as for Sunny-Side-Up, but use 2 tablespoons butter and do not cover pan. Cook until edges turn white, about 1 minute. Begin basting eggs with butter from pan. Cover pan between bastings and continue cooking until whites are completely set and yolks begin to thicken but are not hard, 4 to 5 minutes.
For Steam-Basted Eggs: Cook as for Sunny-Side-Up, but use 1 teaspoon butter or a light coating of cooking spray. Cook until edges turn white, about 1 minute. Add 1 teaspoon water to pan. Cover pan tightly. Continue cooking until whites are completely set and yolks begin to thicken but are not hard, 4 to 5 minutes.
Heat 2 to 3 inches of water, milk, broth, tomato juice, wine or other liquid in a large saucepan or deep skillet to boiling. Adjust heat to keep liquid simmering gently. Break cold eggs, one at a time, into a custard cup or saucer. Holding the dish close to the liquid's surface, slip the eggs, one by one, into the water. Cook until the whites are completely set and the yolks begin to thicken but are not hard, about 3 to 5 minutes. Do not stir. With a slotted spoon, lift out the eggs. Drain the eggs in the slotted spoon or on paper towels. Trim any rough edges, if you like. Adding vinegar or salt to the water to enhance coagulation is not necessary and can flavor the eggs. Use very fresh eggs for poaching. They hold their shape better and form fewer wispy threads or "angel wings" in the water.
Beat together 2 eggs, 2 tablespoons milk or water, salt and pepper, if you like, until blended. Heat a small amount of butter or cooking spray in a 7 to 8 inch nonstick omelet pan or skillet over medium heat until hot. Pour in the egg mixture. As the eggs begin to set, gently pull the eggs across the pan with an inverted turner, forming large soft curds. Continue cooking - pulling, lifting and folding eggs until thickened and no visible liquid egg remains. Do not stir constantly.