The closest thing in appearance in North America is a slice of “Canadian Bacon.”
Unless you are getting a rasher of streaky bacon, you can assume that it will have a lot of meat on it, like what the Americans call “Canadian Bacon.”
Language Notes
Merriam-Webster and American Heritage say that a rasher can also mean a serving or portion of bacon, as in two or three pieces. But this is wrong. North Americans never use the word “rasher”, and only know it in a British context. It may be that some American dictionary writers guessed that a “rasher” equalled a “ration”, as in a portion. But to Brits, who actually use the word, a rasher is always one piece and only one piece. If the proprietor where you are eating is very mean indeed, though, it may well be that that single rasher is also going to be the entirety of your serving…