The Bacon Butty Sandwich: Advertisement DirectionsCook the bacon under a preheated oven grill for seven minutes at about 240C/475F - turning half way through the cooking time. Cook until crispy, but not burnt or too dry. (You can also fry the bacon in a pan if you wish). Butter the two slices of bread and place the grilled or fried bacon inside the two slices of bread to make a sandwich. Add sauces to taste. Enjoy! The bread can also be toasted if you wish! And, you can make this sandwich with a crusty bread roll. The Scientist's Formula: Four researchers at the Department of Food Science at Leeds University in the UK spent more than 1,000 hours testing 700 variations on the traditional bacon sandwich. They tried different types and cuts of bacon, cooking techniques, types of oil and a range of cooking times at different temperatures. A shortlist was then tested with computers to measure the texture of each sandwich. Fifty volunteers also judged each sandwich according to its taste, texture and flavour.