A bacon butty is a British bacon sandwich, and is one of those simple pleasures in life that everyone should experience at least once.
British bacon, not American bacon. My British friends practically go on a rant when the subject of bacon comes up. Now I know why: There is a world of difference between American bacon and British bacon.
American bacon comes from the belly of the hog, is sliced thin, and is very fatty. It's also typically fried until it is crisp.
British bacon comes from the back of the hog (That's why it is also called 'back bacon'), it's sliced thicker and is much less fatty. It s normally fried until it is just brown around the edges and not until it's crisp. Another back bacon is Canadian bacon, so if you want to make a bacon butty without hunting down British bacon you could use Canadian bacon.
I ordered my bacon from Balson Butchers. It's too expensive for daily consumption ($14/pound) but for an occasional treat it is wonderful.
Traditionally, the bread is thick slices of a coarse English bread and not the light thin (almost air) sort of stuff we buy in an American supermarket. I used a toasted English muffin, not because the English muffin is English but because of the flavor and texture.
Butter only. when they smother the bacon in a sauce (usually a brown sauce) it's to mask the fact that they used poor quality bacon. Use high-quality bacon and a little butter is all you need.
Whoever originally said that British food is boring and the British cannot cook does not know what they are talking about. A bacon butty tastes a bit like a ham sandwich that's been taken up a couple of levels. The ham flavor is there, but it's not been overpowered by the saltiness you normally get from salt-cured ham. Combined with the sweet taste of the butter and the crunchiness of the English muffin and you have a really delightful meal.
Eat one of these and you'll never be happy with an Egg McMuffin again.