Sardine sandwich recipe that is quick and easy

These, like salmon sandwiches, are made from materials usually in every household, and can be made at a moment's notice.
Stir four tablespoonfuls of oil into an egg, add a few drops of vinegar or lemon juice. I just use tin sardines, either with tomato or without. Mash them in a bowl, add a tablespoonful of vinegar, or the same amount of lemon juice. If you have lettuce or cress, either shred it, or put one leaf between the fish and the buttered bread. You can also place thin slices of cheese of your choice over the bread and place under hot grill for a minute until the cheese starts to melt. Serve or eat immediatly.