Egg sandwich are made with eggs either hard boiled or fried/scrambled eggs. In the US the most popular variety of the egg sandwich is made from hard boiled eggs sandwiched between sandwich bread with mustard sauce, cheese/butter or mayonnaise along with lettuce at times. Egg sandwiches with Kaiser Rolls, bagels or biscuits along with meats like bacon or ham are also popular combinations in the US for turning the egg sandwich into a full meal.